# Standards for Development and Use of Processor-Based Signal and Train Control Systems

> Briefs, arguments, decisions, and more.

URL: https://www.frixlaw.com/law-library/documents/fr%3A01-19428

## Record

- **Collection:** Federal Register
- **Document type:** Proposed Rule
- **Published:** August 10, 2001
- **Citation:** 66 FR 42352

## Text

DEPARTMENT OF TRANSPORTATION
Federal Railroad Administration
49 CFR Parts 209, 234, and 236
[Docket No. FRA-2001-10160]
RIN 2130-AA94
Standards for Development and Use of Processor-Based Signal and Train Control Systems

AGENCY:

Federal Railroad Administration (FRA), Department of Transportation (DOT).

ACTION:

Notice of proposed rulemaking.

SUMMARY:

FRA is proposing a performance standard for the development and use of processor-based signal and train control systems. The proposed rule also covers systems which interact with highway-rail grade-crossing systems, requirements for notifying FRA prior to installation, and requirements for training and recordkeeping. FRA is proposing these standards to ensure the safe operation of trains on railroads using processor-based signal and train control equipment.

DATES:

Written Comments.
Comments must be received by October 9, 2001. Comments received after that date will be considered to the extent possible without incurring additional expense or delay.

Public Hearings:
Upon specific request, FRA will hold public hearings as appropriate to receive oral comments from any interested party.

ADDRESSES:

Comments should be sent to the Docket Clerk, Docket Management System, U.S. Department of Transportation Room PL 401, 400 Seventh Street, SW., Washington, DC 20590-0001. If you wish to receive confirmation of receipt of your written comments, please include a self-addressed, stamped postcard.

The docket management system is located on the Plaza level of the Nassif Building at the Department of Transportation at the above address. You can review public dockets there between the hours of 9 a.m. and 5 p.m., Monday through Friday, except federal holidays. You can also review comments on-line at the DOT Docket Management System web site at
http://dms.dot.gov.

You may submit comments electronically by accessing the Docket Management System web site at
http://dms.dot.gov
and following the instructions for submitting a document electronically.

FOR FURTHER INFORMATION CONTACT:

William H. Goodman, Staff Director, Railroad Signal Program, Office of Safety, FRA, 1120 Vermont Avenue, NW, Washington, DC 20590 (telephone: 202-493-6325); Grady C. Cothen, Jr., Deputy Associate Administrator for Safety Standards, FRA, 1120 Vermont Avenue, NW, Mail Stop 25, Washington, D.C. 20590 (telephone: 202-493-6302); Cynthia B. Walters, Office of Chief Counsel, FRA 1120 Vermont Avenue, NW, Mail Stop 10, Washington, DC 20590 (telephone: 202-493-6064); or David T. Matsuda, Office of Chief Counsel, FRA, 1120 Vermont Avenue, NW, Mail Stop 10, Washington, DC 20590 (telephone: 202-493-6046).

SUPPLEMENTARY INFORMATION:

I. Statutory Background

The Federal Railroad Administration (FRA) has broad statutory authority to regulate all areas of railroad safety. 49 U.S.C. 20103(a); 49 CFR 1.49. Until July 5, 1994, the Federal railroad safety statutes existed as separate acts found primarily in Title 45 of the United States Code. On that date all of the acts were repealed and their provisions were recodified into Title 49. The older safety laws had been enacted in a piecemeal approach and addressed specific fields of railroad safety. For instance, the Signal Inspection Act, 49 U.S.C. 26 (recodified at 49 U.S.C. 20502
et seq.
(1994)), has in large part governed the installation and removal of signal equipment for most of the previous century.

Pursuant to its general statutory rulemaking authority, FRA promulgates and enforces rules as part of a comprehensive regulatory program to address the safety of railroad track, signal systems, railroad communications, rolling stock, operating practices, passenger train emergency preparedness, alcohol and drug testing, locomotive engineer certification, and workplace safety. For example, in the area of railroad signal and train control systems, FRA has issued regulations, found at 49 CFR part 236 (“Part 236”), addressing the security of signal apparatus housings (49 CFR 236.3), location of roadway signals (49 CFR 236.21), and the testing of relays (49 CFR 236.106). Hereafter all references to parts shall be parts located in Title 49 of the Code of Federal Regulations.

II. Regulatory Background

Part 236 was last amended in 1984. At that time, signal and train control functions were performed principally through use of electrical circuits employing relays as the means of effecting system logic. This approach had proven itself capable of supporting a very high level of safety for over half a century. However, electronic controls were emerging on the scene, and several sections of the regulations were amended to take a more technology-neutral approach to the required functions (see §§ 236.8, 236.51, 236.101, 236.205, 236.311, 236.813a). This approach has fostered introduction of new, more cost effective technology while providing FRA with strong enforcement powers over systems that fail to work as intended in the field.

Since that time, FRA has worked with railroads and suppliers to apply the principles embodied in the regulations to emerging technology and to identify and remedy initial weaknesses in some of the new products. As a result, thousands of interlocking controllers and other electronic applications are embedded in traditional signal systems. Further technological advances may provide additional opportunities to increase safety levels and achieve economic benefits as well. For instance, implementation of innovative positive train control (PTC) systems may employ new ways of detecting trains, establishing secure routes, and processing information. This presents a far greater challenge to both signal and train control system developers and FRA. This challenge involves retaining a corporate memory of the intricate logic associated with railway signaling, while daring to use whole new approaches to implement that logic—at the same time stretching the technology to address risk reduction opportunities that previously were not available. For FRA, the challenge is to continue to be prepared to make safety-based decisions regarding this new technology, without impairing the development of this field. Providing general standards for the development and implementation of products utilizing this new technology is needed to facilitate realization of the potential of electronic control systems and for safety and efficiency.

FRA has already used its authority to grant waivers and issue orders to support innovation in the field of train control technology. FRA has granted test waivers for the Union Pacific (UP)/Burlington Northern Santa Fe (BNSF) Positive Train Separation (PTS) project in the Pacific Northwest, the National Railroad Passenger Corporation (“Amtrak”) Incremental Train Control System (ITCS) in the State of Michigan, the CSX Transportation Inc. (CSX) Communication-Based Train Management (CBTM) project in Georgia, and the Alaska Railroad PTC project. FRA recently granted conditional

revenue demonstration authority for ITCS. In 1998, FRA issued a final order for the installation of the Advanced Civil Speed Enforcement System (ACSES) on the Northeast Corridor (63 FR 39343, Aug. 21, 1998). See also 64 FR 54410, Oct. 6, 1999 (delaying effective date of such order).

Although FRA expects to continue its support for responsible tests, demonstrations, and implementations, the need for controlling principles in this area is becoming increasingly obvious. This rulemaking provides the forum for identifying and codifying those principles.

FRA's need to review its regulatory scheme with respect to emerging technology in the signal and train control arena was acknowledged by Congress in Section 11 of the Rail Safety Enforcement and Review Act (RSERA) (Pub. L. 102-365, Sep. 3, 1992), entitled “Railroad Radio Communications.” The RSERA mandated that the Secretary conduct a safety inquiry to assess, among other areas, the status of advanced train control systems and the need for federal standards to ensure that such systems provide for positive train separation and are compatible nationwide. FRA conducted such an inquiry and submitted a comprehensive Report to Congress on July 8, 1994.

As part of this Report, FRA called for implementation of an action plan to deploy PTC systems (“Railroad communications and Train Control,” FRA, July 1994). The report forecast substantial benefits of advanced train control technology to support a variety of business and safety purposes, but noted that an immediate regulatory mandate for PTC could not be currently justified based upon normal cost-benefit principles relying on direct safety benefits. The report outlined an aggressive Action Plan implementing a public/private sector partnership to explore technology potential, deploy systems for demonstration, and structure a regulatory framework to support emerging PTC initiatives.

Following through on the Report, the FRA committed approximately $40 million through the Next Generation High Speed Rail Program and the Research and Development Program to support development, testing and deployment of PTC prototype systems in the Pacific Northwest, Michigan, Illinois, Alaska, and the Eastern railroads' on-board electronic platforms. As called for in the Action Plan, the FRA also launched an effort to structure an appropriate regulatory framework for facilitating implementation of PTC technology and for evaluating future safety needs and opportunities. For such a task, FRA desired input from the developers, prospective purchasers and operators of this new technology. Thus, in September of 1997, the Federal Railroad Administrator (“Administrator”) asked the Railroad Safety Advisory Committee to address several issues involving PTC.

III. Railroad Safety Advisory Committee (RSAC)

A. RSAC

Since 1993, FRA has been taking action to promote earlier and more extensive participation by all interested parties in the agency's regulatory processes. That year, the Administrator conducted a series of roundtables on all aspects of FRA's safety program. FRA initiated its first formal negotiated rulemaking in 1994 on the topic of roadway worker safety.

FRA also conducted outreach and a review of its regulatory program under the President's Regulatory Reinvention Initiative and the National Performance Review. FRA concluded that railroad safety would be best served if the agency varied its traditional “hear and decide” regulatory style to a new one founded on consensus among those who are benefitted and burdened by the agency's regulations. Implicit in this change is the concept that decisions regarding the best approach to resolution of safety issues should be made with the full participation of all affected parties.

In March 1996, FRA established the RSAC, which provides a forum for consensual rulemaking and program development. The Committee includes representation from all of the agency's major customer groups, including railroads, labor organizations, suppliers and manufacturers, and other interested parties. A list of member groups follows:

American Association of Private Railroad Car Owners (AARPCO)

American Association of State Highway & Transportation Officials (AASHTO)

American Public Transit Association (APTA)

American Short Line and Regional Railroad Association (ASLRRA)

American Train Dispatchers Department/BLE (ATDD/BLE)

Association of American Railroads (AAR)

Association of Railway Museums (ARM)

Association of State Rail Safety Managers (ASRSM)

Brotherhood of Locomotive Engineers (BLE)

Brotherhood of Maintenance of Way Employes (BMWE)

Brotherhood of Railroad Signalmen (BRS)

High Speed Ground Transportation Association

Hotel Employees & Restaurant Employees International Union

International Association of Machinists and Aerospace Workers

International Brotherhood of Boilermakers and Blacksmiths

International Brotherhood of Electrical Workers (IBEW)

Labor Council for Latin American Advancement (LCLAA) (non-voting)

League of Railway Industry Women (non-voting)

National Association of Railroad Passengers (NARP)

National Association of Railway Business Women (non-voting)

National Conference of Firemen & Oilers

National Railroad Construction and Maintenance Association

Amtrak

Railway Progress Institute (RPI)

Safe Travel America

Secretaria de Communicaciones y Transporte (non-voting)

Sheet Metal Workers International Association

Tourist Railway Association Inc.

Transport Canada (non-voting)

Transport Workers Union of America (TWUA)

Transportation Communications International Union/BRC (TCIU/BRC)

United Transportation Union (UTU)

National Transportation Safety Board (NTSB) (non-voting)

Federal Transit Administration (FTA) (non-voting)

When appropriate, FRA assigns a task to RSAC, and after consideration and debate, RSAC may accept or reject the task. If accepted, RSAC establishes a working group that possesses the appropriate expertise and representation of interests to develop recommendations to FRA for action on the task. These recommendations are developed by consensus. If a working group comes to consensus on recommendations for action, the package is presented to the RSAC for a vote. If the proposal is accepted by a simple majority of the RSAC, the proposal is formally recommended to FRA. If the working group is unable to reach consensus on recommendations for action, FRA moves ahead to resolve the issue through traditional rulemaking proceedings.

Recommendations from RSAC come in all varieties. RSAC may recommend continued implementation of existing measures, voluntary initiatives by individual parties, concerted voluntary initiatives by several parties, amendment of existing regulations, new regulatory requirements, or enactment

of legislation, as appropriate. The advice and recommendations of RSAC form the basis for this proposed rule.

On September 30, 1997, the RSAC accepted a task (No. 97-6) entitled “Standards for New Train Control Systems.” The purpose of this task was defined as follows: “To facilitate the implementation of software based signal and operating systems by discussing potential revisions to the Rules, Standards and Instructions (Part 236) to address processor-based technology and communication-based operating architectures.” The task called for the formation of a working group to include consideration of the following:

• Disarrangement of microprocessor-based interlockings;

• Performance standards for PTC systems at various levels of functionalities (safety-related capabilities); and

• Procedures for introduction and validation of new systems.

RSAC also accepted two other tasks related to PTC, task Nos. 97-4 and 97-5. These tasks dealt primarily with issues related to the feasibility of implementation of PTC technology.

B. The PTC Working Group

FRA gratefully acknowledges the participation and leadership of representatives of the following organizations who served on the PTC Working Group:

AAR, including members from

BNSF

Canadian National

Conrail

CSX

Metra

Norfolk Southern Railway Company

UP

Amtrak

AASHTO

APTA

ASLRRA

ATDD/BLE

BLE

BMWE

BRS

FRA

FTA (non-voting)

HSR/MAG LEV

IBEW

NTSB (non-voting)

RPI

UTU

In order to efficiently accomplish the three tasks assigned to it involving PTC issues, the PTC Working Group empowered two task forces to work concurrently: the Data and Implementation Task Force, which handled tasks 97-4 and 97-5, and the Standards Task Force, which handled task 97-6.

The Data and Implementation Task Force finalized a report on the future of PTC systems and presented it, with the approval of RSAC, to the Administrator on September 8, 1999. Report of the Railroad Safety Advisory Committee to the Federal Railroad Administrator, “Implementation of Positive Train Control Systems,” (September 8, 1999). The Data and Implementation Task Force will be involved in monitoring implementation of PTC technology on the joint Illinois/AAR/UP/FRA project.

The Working Group also employed several teams, comprised of representatives from RSAC member organizations, who provided invaluable assistance. An Operating Rules Team was charged with working to ensure that appropriate railroad operating rules are part of any PTC implementation process, and a Human Factors Team was charged with evaluating human factor aspects of PTC systems. Members of these teams serve on both the PTC Standards Task Force and the Data and Implementation Task Force, and additional team members were drawn from the railroad community.

In addition to providing assistance from FRA staff and staff from the Volpe National Transportation Safety Center, FRA responded to a consensus request from the Standards Task Force by contracting for assistance from the Center for Safety-Critical Systems at the University of Virginia.

C. The Standards Task Force

The Working Group, consisting of both the Data and Implementation Task Force and the Standards Task Force, held a meeting at Ponte Vedra Beach, Florida in November 1997 to set the direction of the Standards Task Force. An informal first meeting of the Standards Task Force was held in Washington DC on December 18, 1997, followed by the first formal meeting on February 25, 1998, in Fort Worth, Texas. The Standards Task Force is primarily responsible, with the FRA Office of Chief Counsel and Office of Safety, for drafting this proposed rule.

After the initial informal meeting, the Standards Task Force met almost every month until the last meeting in New Orleans, LA on June 28-29 of 2000. Much documentation was produced at these meetings, due to extensive discussions, presentations and tutorials. This documentation has been placed in the docket for this rulemaking.

The primary mission of the Standards Task Force was to develop regulations that would address the new PTC systems, as well as subsystems and components thereof. PTC systems were described as achieving three core functions: (1) Preventing train-to-train collisions (positive train separation); (2) enforcing speed restrictions, including civil engineering restrictions and temporary slow orders; and (3) providing protection for roadway workers and their equipment operating under specific authorities.

At each meeting, proposed standards were continually developed and modified. The text of the proposed regulation became known as the “Master Draft.” Four primary stakeholder groups worked on the Master Draft and presented their own views and opinions as to what should be included in the regulations. As such, consensus was very difficult to obtain. The four stakeholder groups involved were: (1) The federal government, (2) railroad management, (3) railroad labor, and (4) railroad signal and train control system suppliers. The first three groups had voting powers. The supplier group did not have voting powers, but their input was essential and valuable to the other interest groups, especially railroad management, their primary customers. All Standards Task Force meetings were open to all interested parties, and on the average, 30 to 35 people attended. The final two meetings recorded over 50 attendees each. Any attendee was considered a member of the Standards Task Force and had the right to express an opinion at the meeting. However, when consensus was called for, only actual voting members from the PTC Working Group were counted.

In December 1999, the Standards Task Force reached consensus on most outstanding issues. Chiefly, these included the adoption of risk assessment criteria, requirements for independent third party review of validation and verification, applicability of the proposed rule to existing systems, life cycle recordkeeping and reporting, and related matters.

On June 29, 2000, the Standards Task Force presented its consensus recommendation to the entire working group. The PTC Working Group accepted the recommendation with minor changes and forwarded its consensus recommendation to RSAC, which approved it on September 14, 2000.

IV. Major Issues

A. Why a Performance-Based Approach?

What is a Performance Standard?

During the Standards Task Force discussion, FRA noted that the existing “Rules, Standards and Instructions” (Part 236) take a performance-oriented approach at the functional level,

although—by virtue of the historical context in which they were initially prepared—they most often reference older technology. During the last decade and a half, this performance-oriented approach to specified functions has permitted the growth of electronic systems within signal and train control systems without substantial regulatory change (albeit with growing ambiguity concerning the application of individual provisions to novel technical approaches). Wishing to maintain historical continuity and hasten preparation of a proposed rule, FRA offered for consideration an initial redraft of Part 236 that attempted a more technology-neutral approach to performance at the functional level, while also addressing PTC functions, as a possible starting point for the group's work.

Carrier representatives found the FRA draft to be unduly constricting, and asked that the group pursue higher-level performance standards. Supplier and labor representatives agreed to this approach, and FRA has endeavored to support the Standards Task Force in pursuing it.

Early in the deliberations of the Standards Task Force, carrier representatives requested that FRA arrange presentations on the use of performance standards in lieu of prescriptive regulations. The group heard from representatives of the Research and Special Programs Administration (RSPA), Federal Highway Administration's Office of Motor Carrier Safety (now Federal Motor Carrier Safety Administration (FMCSA)), and APTA. FRA distributed a guidance document entitled “Performance Standards: A Practical Guide to the Use of Performance Standards as a Regulatory Alternative,” (Project on Alternative Regulatory Approaches, September 1981), a copy of which has been placed in the docket of this rulemaking.

In brief overview, the term “performance standard” has been variously applied to describe many different forms of regulatory approaches that avoid design specifications and other prescriptive requirements, such as mandates that actions be taken in a particular sequence, or in a particular manner, by the regulated entity. At the most permissive extreme, a performance standard for a railroad operating system might specify an “acceptable” level of safety performance (e.g., number of fatalities per million train miles) and avoid any intervening action unless and until the performance of the regulated entity fell below that level. FRA believes that this type of approach would represent an abandonment of the agency's responsibility to promote safety, since it would necessarily assume optimum performance by the regulated entity (a condition not realized in practice) and would prevent helpful intervention until unacceptable consequences had already occurred. The Working Group has not sought to pursue this approach.

The least permissive performance standards include such approaches as requiring that a metal skin on the front of a locomotive have penetration resistance equivalent to that of a given thickness of a specified steel. In this example, the choice of material is left to the designer, but the options are not extensive.
See,
e.g., 49 CFR 238.209.

In the middle range of permissiveness, a performance standard might address acceptable performance parameters for a particular, mandated device, in lieu of a fixed physical description. For instance, FRA requirements for railroad tank cars carrying flammable compressed gas require the application of high temperature thermal protection that can be accomplished using a variety of materials, together with pressure relief valve capacity requirements adequate to permit safe evacuation and burn-off of the car's contents prior to catastrophic failure of the vessel in a fire environment (part 179, appendix B (qualification test procedure)). This combination of regulatory requirements has been highly effective in preventing loss of life from violent detonation of tank cars involved in derailments (although compliance issues have been presented by disintegration of insulation blankets that could not be readily detected under the outer jacket of a car).

Some of the safety statutes administered by FRA contain performance-related criteria. For instance, the Signal Inspection Act, as codified at 49 U.S.C. 20502(b), states:

A railroad carrier may allow a signal system to be used on its railroad line only when the system, including its controlling and operating appurtenances . . . may be operated safely without unnecessary risk of personal injury.

However, recognizing the need to make a practical application of this broad statement, the law also requires that the system “has been inspected and can meet any test prescribed under this chapter.” What could otherwise be deemed a very broad performance standard is thus made more specific in practice (though just how specific the requirements should remain is one of the subjects of this proceeding).

Criteria for Evaluation of Performance-Related Approach

The discussion that follows identifies some of the general considerations that apply to use of performance standards and some of the practical factors that come into play with respect to the safety of processor-based signal and train control technologies.

In response to the report of the Vice President's Commission on Aviation Safety and Security, the Federal Aviation Administration (FAA) published a brief “Performance-Based Regulations Guide” (October 31, 1997). That guide notes four “substantive criteria” that can be used to determine whether regulations can be written in a performance-based manner:

1. Can the regulatory requirement be stated in terms of a practical goal that can be understood by an individual or company (e.g., meeting a prescribed climb gradient with one engine inoperative)?

2. Will a regulation stated in performance terms be enforceable?

3. Will a performance-based regulation discriminate against smaller companies?

4. Is it possible to establish an equivalency rule that will itself be considered a performance-based regulation? (In FAA terminology, “an equivalency rule” is one that is based upon a command-and-control requirement but allows the regulated party to demonstrate that an alternative approach provides an equivalent level of safety.)

The FAA guide noted performance-based regulations should not be used if:

1. Congress has mandated a specific outcome (e.g., “no smoking” on domestic flights).

2. The standard would be so vague as to be unenforceable (e.g., “fly safely”).

3. The FAA cannot agree on an acceptable alternative to a command-and-control standard (e.g., the age 60 rule [for air transport pilots] could be eliminated only if the FAA could prescribe medical and flight testing standards that would provide an equivalent level of safety).

These criteria are generally applicable to the issue presented by this proposal, and other possible concerns can be added. For instance, what if administration of a performance standard would involve too much cost to all regulated entities, small entities only, or the government? What if the performance standard is clear, but verifiable only after the fact and thus enforceable only in a reactive sense? What if the standard is very clear, but the analytical techniques needed to

verify compliance are poorly developed or are not validated?

FRA has identified several criteria of its own with respect to promulgating a performance standard for this area of regulation: simplicity, relevancy, reliability, cost, and objectivity.

First, FRA feels the standard should be simple, because it will apply to many regulated entities. If the standard requires complex mathematics, there may be no way for many of the entities to comply, and if complicated enough, the standard may be beyond FRA's capacity to enforce. For instance, the Standards Task Force has been exposed to many briefings on mathematical techniques used to measure product safety. Often, the mathematics were extremely complicated, the issues surrounding selection of a model so esoteric that only a small fraction of the expert population present fully understood the issues, and at no point was there a consensus that any particular technique was technically superior.

Second, FRA feels the standard should be relevant with respect to safety. There may be many convenient measurable qualities of processor-based systems which are not relevant to safety. For example, the mean time to repair a product subsystem may or may not necessarily be relevant to safety, depending upon the backup method of operation in place.

Third, FRA believes the standard should be reliable in that the test applied should yield similar results each time it is applied.

Fourth, FRA believes demonstrating compliance with the standard should not be unduly expensive. Train control systems have a very good safety record. The cost of proving compliance with the standard should not cost more than the benefits it will bring. Furthermore, a standard could be so exacting that it would prevent the deployment of systems which would very likely improve safety, but which do not meet some extremely difficult or expensive test. Thus a purported safety standard might actually impose safety costs.

Fifth, FRA feels the standard should be objective. A completely objective standard would allow for compliance to be determined through scientific study or investigation. This is critical from a regulatory perspective, because FRA feels it would not be fulfilling its safety mission if it could not verify compliance with the performance standard. Also, an objective standard would allow for sound business planning with respect to budgeting for and development of processor-based systems. Thus, FRA can realize additional safety benefits from this standpoint.

Development of the Proposed Standard

The Standards Task Force considered only two different performance standards, yet determining an adequate method for demonstrating compliance was the key factor in the Standards Task Force's final decision.

The first standard proposed for discussion by the Standards Task Force was a standard which would have required that the implementation of proposed systems lead to safety improvements of 33% to 50%. This standard was proposed in order to address the uncertainties involved in the safety determinations. The theory behind the proposal was that an actual increase in safety by a discrete relative amount would overcome any uncertainties involved in the safety assessment process. In addition to the objectivity problems involved in not necessarily requiring a certain level of confidence in the safety measurements, the most disconcerting issue to the group was the cost of such a standard. It would impose burdensome safety and operational costs. The safety costs would result primarily from railroads not being able to replace products with those which would improve safety by less than the desired margin. The operational costs would result from not being able to replace a product with one that was equally as safe, but less costly. These shortcomings were too severe for the Standards Task Force to warrant further consideration of this option.

The only other performance standard considered by the Standards Task Force was the one which led to the proposed rule: that new products must not degrade safety. This standard was not formally agreed to by the Standards Task Force until a means for demonstrating compliance could be agreed upon. The remainder of the discussions focused on the various ways in which compliance with this standard could be determined, and which of them is the most appropriate.

The first proposal under this standard would have required a comparison of the sample means of the distributions of risk for the proposed product and the current system. This proposal would require demonstration with a minimum ninety-five percent confidence level that the likelihood that the distribution of risk for the proposed system is not less than the sample mean for the current system. The Standards Task Force found cost to be the most serious concern with this proposal. For relatively simple products this approach may be cost-effective. It would be moderately expensive, as it requires some modeling of the risk, but the cost of modeling might still be less than the costs of complying with a specification standard. The most significant costs would be incurred when a proposed system takes advantage of current-generation, high-capability processors. The expense of computing time required to generate statistically significant modeling results would be prohibitive.

A slightly different approach would be to test the standard deviations of the differences in sample means. This approach is not much more complicated than simply testing against the standard deviations. The cost would be roughly the same, however, this approach would pose reliability problems. If the number of simulation cycles were held to a fixed ratio between cycles for the current system and cycles for the proposed product, the standard deviation of the sample mean would decrease in proportion to the square root of the number of simulation cycles. Furthermore, the looseness of the assumptions would affect reliability of this approach as a measurement tool. There could also be significant problems with non-random re-selection of paths in simulations.

The next approach proposed was to weight each risk calculation by a factor of uncertainty, and then run the simulation to see what the relationship is between current risk levels and levels of risk associated with use of the proposed product. This approach would require a higher level of confidence for a lower subjective confidence in the underlying assumptions. This option is more complex than any yet discussed by the Standards Task Force, and does not appear to be either reliable or objective. The Standards Task Force ultimately concluded that this test is too subjective for their purpose.

Also suggested was an approach utilizing statistics of extremes, or extreme value theory. This objective technique is favored for risk analysis in civil engineering and environmental science applications and is designed to overcome the problems which arise when using traditional distribution models to analyze low probability, high consequence events. It is sufficiently complex that there was no consensus in the group as to its effectiveness for train control applications, although the University of Virginia continues to provide the group with more information on this technique. An informal survey of group members revealed that fewer than one tenth of an expert group claimed to be familiar with extreme value analysis. Thus, the Standards Task Force concluded

unfamiliarity with this approach within the industry would probably make it expensive to require.

The final mathematical approach suggested was described as a Bayesian belief network. This is also a complicated test, which appears not totally objective. This approach would require the railroad to show by some high evidentiary standard, such as “demonstrating to a high degree of confidence,” that the proposed product would result in no loss of safety. It is this final test which FRA proposes. The Standards Task Force has developed more specific criteria for satisfying the performance standard under this approach using current safety engineering practices and principles within the industry.

Although advantages of and concerns with the proposed standard are addressed in the sections which follow, FRA seeks comments addressing the decisions reached by the Standards Task Force concerning the various standards and compliance methodologies considered and rejected.

Advantages of a Performance-Based Standard

This NPRM presents the highest level performance requirements ever attempted by FRA. To informed advocates of performance-based regulations, the reasons for taking this course are obvious. The emerging technologies documented in the RSAC's Report to the Administrator (“Implementation of Positive Train Control Systems,” September 8, 1999), reflect an extensive array of electronic applications, including short-range radio frequency (RF) data links (transponders), medium-range RF data links, train location systems employing GPS/DGPS positioning supported by inertial guidance and track database analysis, and logic controllers placed at central office locations, on the wayside and onboard trains. Inputs may be derived from a variety of on-board systems, automatic equipment identification systems, two-way end-of-train telemetry, existing signal and train control systems, and other sources. Additional technologies are on the horizon, and others will no doubt emerge between the date of publication of a final rule in this proceeding and the next revision of the regulations by FRA.

While some new train control systems may not yield all of the same safety benefits that are supported by traditional track circuits (e.g., detection of some broken rails), they may be capable of very nearly eliminating train-to-train collisions and addressing the other PTC core functions. Data derived from train control applications may be used for improved train management, crew management, and other business purposes. Ultimately, PTC technology may permit the transfer of train movement information for use in providing warning at highway-rail grade crossings under conditions that are, today, prohibitively expensive.

In short, the future benefits of emerging railway electronic systems will be substantial, and suppliers and carriers will need a great deal of flexibility to avoid inadvertent limitations on the growth of important safety systems. This rulemaking was commenced to facilitate introduction of these new technologies. A performance-based approach should be the most powerful means of accomplishing that objective because it would:

• Provide the maximum flexibility to design capable systems, increasing the likelihood that all possibilities will be carefully explored;

• Permit designers to optimize systems to address safety and other needs, making systems more attractive to those making capital allocation decisions; and

• Avoid inappropriate requirements that could drive up costs and put the technology out of reach for years to come.

Concerns With a Performance-Based Standard

This notice embodies a very high-level approach to performance standards that would offer unprecedented flexibility for carriers to design and deploy new signal and train control technologies. At the same time, it would require extensive documentation of the safety of the system prior to its introduction in revenue service. This approach has many profound advantages, and notable disadvantages, that deserve scrutiny in this rulemaking.

FRA has also noted significant obstacles to successful implementation of performance standards in this context, as well as reservations with respect to the utility of such standards. These concerns are sufficient to warrant caution and a vigorous public debate.

The first concern that has arisen is the static nature of a fixed performance standard grounded in current safety performance levels. As noted above, this proceeding is intended to facilitate safety improvement through accelerated introduction of new technology. The proposed performance standard described below, which basically provides that the safety of a new system may not fall below the base condition (existing technology, with certain adjustments), sets a modest objective for suppliers and railroads. However, progress is not the inevitable result of technological innovation. It is at least theoretically possible for a railroad to claim greater efficiencies associated with new technology, add modest safety enhancements that go beyond the capabilities of existing signal technology, but delete certain functionalities associated with the existing system or implement the system in a manner that includes significant safety vulnerabilities. The net result could be cost savings with no advance in safety. Yet, unlike today, FRA would lack leverage under the regulations to insist that known vulnerabilities in the system be corrected, even if that could be done on a highly cost effective basis. (FRA would retain its general authority under the Signal Inspection Act, but the extent to which that authority might be impaired could only be determined after extensive litigation, should its exercise be challenged.)

The thought that a performance standard might stagnate safety improvements is not a fanciful concern. Since economic deregulation of the railroad industry (signified most notably by enactment of the Staggers Rail Act of 1980), railroads have progressed toward profitability principally by cutting costs. Strong intermodal competition has caused the railroads to turn much of the resulting savings back to shippers in the form of reduced contract rates. Particularly in the wake of major mergers and consolidations (a condition applicable to each of the four largest railroads today), the pressure from the financial community for cost reduction is particularly strong. This has sometimes led to management decisions based on short-term considerations. FRA regularly deals with the effects of this phenomenon in the context of Safety Assurance and Compliance Programs on the various properties.

Clearly, the railroads have managed to improve their overall safety performance during the past 20 years while also cutting costs, in part by using technology to good advantage. However, the low-hanging fruit is largely gone. Managers and employees are increasingly asked to do more with less, which is a confining business practice. Properly implemented, new signal and train control technology can help reduce workload requirements while also improving asset utilization. Improperly implemented, the technology could stagnate safety improvements.

Second, doubt remains whether the relevant technical, scientific, and railroad signaling communities are fully

prepared to support implementation of this rule. FRA has funded significant research into the safety of processor-based systems.
See, e.g.,
“Analytical Methodology for Safety Validation of Computer Controlled Subsystems,” (Luedeke, John, (Battelle) for Volpe National Transportation Systems Center; DOT-VNTSC-FRA-95-8 (April 1994)). Administration of existing regulations, including consideration of waivers associated with novel train control proposals, has provided FRA with the opportunity to become familiar with strengths and limitations of the safety programs of major signal suppliers. Field compliance efforts have provided a reasonably good view of railroads' efforts to implement processor-based technologies. FRA's observations from this experience follow.

The field of system safety for safety-critical control systems is relatively young and remains in flux. Military Standard 882C, “System Safety Program Requirements” (U.S. Department of Defense; January 18, 1993), provides an overall framework for safety planning and analysis. A growing body of literature documents good practice in the field.
See, e.g.,
Leveson, Nancy G., “Safeware: System Safety and Computers,” Addison Wesley Publishing Company, Inc., 1995. FRA purchased and distributed to Standards Task Force members copies of “Safety-Critical Computer Systems” (Storey, Neil; Addison-Wesley Longman (Harlow, England 1996)), a text addressing the subject matter in a way characterized as suitable for a final-year undergraduate or masters-level program in engineering. The FAA, the Nuclear Regulatory Commission, and other Federal agencies have addressed this issue in various ways and continue to conduct relevant research. Parallel efforts internationally include the European Committee for Electrical Standardization (CENELEC) standard prEN50129 “Railway Applications—Safety-Related Electronic Systems for Signaling,” (May 18, 1998).

Railroad signal suppliers maintain a strong emphasis on the safety of their systems. However, formal processes to conduct and document safety analyses for new products are not uniform in their content; and FRA is aware of departures from what might be deemed acceptable within the framework of a rule implementing the proposals set forth below. In general, suppliers employ varying safety assurance concepts for their products and are not currently able to provide quantitative information concerning the projected life-cycle safety performance of new products. The vigorous emphasis on more formal methods of safety assurance in the supply community is exemplified by the recent adoption by the Institute of Electrical and Electronic Engineers, Inc. (IEEE), of the new “Standard for the Verification of Safety for Processor-based Systems Used in Rail Transit Control” (No. 1483). The lack of complete consensus on the issue of proofs of safety is perhaps best exemplified by the fact that the IEEE standard just referenced does not address validation of these systems.

Recognizing that any performance standard must provide a level playing field for the supply community and clear decisional criteria for FRA's review of safety documentation, FRA asked the Standards Task Force to focus specifically on the requirements for verification and validation and the associated quantization of safety (further discussed below). Although the supply community representatives were able to agree with other Standards Task Force members on general principles that should apply to these safety processes and the metric of Mean Time to Hazardous Event (MTTHE), suppliers were not able to agree to provide estimates of MTTHE based on fully quantitative inputs derived from uniform analytical methods. The possibility remains, therefore, that estimates of residual risk from different suppliers might have different meanings and be based on differing levels of confidence. As public comment is received and considered, FRA will continue to work with the parties to ensure that information provided in support of various products is reasonably comparable.

FRA has also funded research into the application of risk assessment techniques to railroad operations and has made use of risk studies in the development of its own rules and in the evaluation of system safety estimates presented by various parties. Although FRA decision-making with respect to safety has always been founded on a keen appreciation for the elements of risk (event likelihood, severity, and an appropriate means for normalizing exposure), FRA recognizes that future advances in safety and transportation efficiency will necessitate a heavier reliance on often complex risk assessment techniques, as well as system safety principles. Quantitative risk assessments can enlighten decision making by taking into consideration a variety of relevant factors, providing a means of testing the sensitivity of key assumptions, and projecting the risk environment into the future. In an ideal circumstance, risk assessment may help identify critical system safety decisions and shed light on their mitigation well before the potential for hazardous events is realized in the field.

However, at the outset it must be said that use of risk assessment to determine compliance with performance criteria embodied in a regulation presents an awkward problem. Practitioners of risk assessment are the first to point out that they do not purport to provide information that will predict actual levels of performance. Rather, they provide analysis that suggests the “relative safety” of the projected system in relation to a base case construct against which it is evaluated. This is a particularly powerful technique to improve the safety of a system, if properly executed. But the results do not constitute direct proof that a particular level of safety will be achieved.

Obviously, this problem could be “solved” by simply requiring that an analysis meeting certain criteria show an improvement in safety. However, FRA believes that this approach would ask the wrong question and result in an increasingly parochial focus on the techniques of risk assessment and their proper execution, to the exclusion of the concrete safety issues presented by particular systems. FRA was not established to regulate risk assessment techniques, and attempting to do so would only inhibit the growth of the discipline. Accordingly, FRA has insisted that the proposed performance criterion be stated in absolute terms, with latitude afforded to scale the analytical effort to the problem at hand. Obviously, in the end FRA would have to be convinced that the particular showing was persuasive with respect to the likelihood that the new system would meet or exceed the safety performance of the existing system.

Further, quantitative risk assessment as applied to the safety of railroad operations is best viewed as an art, rather than a science. A proper analysis must correctly describe salient elements of the operating system, correctly assess the contribution of the risk dimension under review to key scenarios, accurately estimate the frequency with which the risk will arise, accurately describe the severity of hazardous events that may occur, and fairly evaluate the impact of mitigating measures on the prevention, or reduction in severity, of the hazardous event. This requires that the analyst(s) be fully conversant with the railroad operating system, that input data be available (and be properly selected if various data are available), that the analysis be structured to produce a credible result, and that the result be

appropriately characterized. There are challenges associated with each of these steps.

FRA is also concerned that a requirement for a risk assessment based on probability or likelihood will refocus safety efforts during development from optimization to post-design justification. That is, FRA fears that the focus will shift to proving that the product is safe enough after it has been designed. This concern is fueled by such facts as: (1) Subsystems and components involving software and/or human factors do not readily lend themselves to risk quantization as electro-mechanical ones do, (2) risk calculations for current operations will most likely be limited in precision, and (3) early FRA involvement in the product development process is not mandated. As William D. Ruckelshaus, former two-time Director of the U.S. Environmental Protection Agency (EPA), has pointed out, “risk assessment data can be like the captured spy; if you torture it long enough, it will tell you anything you want to know.” Leveson at 60.

In practice, FRA has had occasion to substantially discount the value of risk assessments in some cases, while relying heavily on the results (together with other information) in other cases. FRA expects that the quality of risk assessment practice will improve over time, as experience is gained and as peer review strengthens the quality of analysis.

Recognizing the need to advance the state of the art with respect to analysis of risk specifically associated with various methods of operations and train control technologies, the Standards Task Force established a team to support development of an “Axiomatic Safety-Critical Assessment Process” (ASCAP). At the request of the Standards Task Force, FRA engaged the University of Virginia to develop the ASCAP model as a risk assessment “toolkit” for use in implementing this proposed rule. The initial challenge for the ASCAP team and contractor has been to describe the relative safety of the current method of operation on a CSXT line which is operated without a signal system using direct traffic control system rules (the “base case”). The first comparison case will be the safety of operations on the same line should a traffic control system be installed. The second comparison case will be implementation of the proposed CBTM system, an innovative technology that addresses the PTC core functions.

As this proposed rule was being finalized for review and publication, the ASCAP effort was progressing toward generation of the base case and an initial comparison case. The University of Virginia principal researcher continued to meet with the ASCAP team providing peer review and support for the project. Data was being assembled and reviewed for suitability. A Human Factors Team had been established to assist in formulating input assumptions with respect to the anticipated actions of employees under various conditions associated with the three methods of operations.

FRA believes that the ASCAP model (more fully described below) will represent a significant step forward in the quality of risk assessment methodologies related to train control. If successful, the technique may provide a level of analytical refinement significantly exceeding other known techniques. However, the success of this effort is not inevitable, given the degree of technical difficulty, the relative paucity of detailed data available for use within the model, and the uncertainties with respect to the role of human factors under the three cases. (For instance, CSXT and it employees who will be responsible for maintenance of various aspects of the system have not had experience with respect to maintenance of CBTM in the field. It may be difficult to project all failure modes that could be associated with routine maintenance and with modification of the system over its life cycle.) While it should be possible to benchmark the estimated risk for the base case and the traffic control system against experience on the CSXT line and for similar operations nationally, being certain of the validity for the CBTM case would require extensive, long-term experience in revenue service.

Indeed, for many risk assessment problems, the base case will not be “known” in a statistical sense before the work begins because there will not have been sufficient exposure in the specific territory affected, under current or projected conditions, to make collision and other data representative of actual long-term performance. This will require somewhat elaborate construction of a base case scenario (as in the current CSXT “dark territory” case mentioned immediately above) to permit consideration of the extent to which local conditions may affect national statistics that could otherwise be applied to the problem.

The Standards Task Force has discussed the fact that some margin of error will be associated with both base and comparison cases in any risk assessment. The group has discussed the need to employ sensitivity analysis to determine the effect of key assumptions and the desirability of putting a value on the extent to which the underlying analysis supports confidence in estimated risk, expressed as a point value or range. After examining several options, the group agreed to a standard fairly characterized as one of reasonableness, with respect to the current state of the art.

Whatever formal risk values emerge from an assessment conducted in conformity with the proposed rule, some statistical variability would apply to post-implementation review of systems. This is true both because risk assessments will provide an imperfect view of a very complex reality, but also because the wide dispersion of the pertinent risk and the seemingly random nature of potentiating events (e.g., a maintenance of way employee leaving a switch open on the main line) make precise predictions impossible. For instance, take the case of removal of an existing automatic block system (ABS) and its replacement by a non-vital communication-based train control system overlaid on track warrant control. The safety documentation for this “product,” as reviewed under this proposed rule (including part 235), might show an actual accident history of 2 severe events in the last 20 years, an estimated base risk level of 2.5 such events, and a predicted accident frequency for the new system of one severe event over 20 years into the future. Should the actual experience under the new system (with no change in traffic levels) be one severe event and one moderate event in the first five years, this could indicate the emergence of risk factors not foreseen when the analysis was conducted or simply the occurrence of events well within the range of expected outcomes.

FRA is particularly concerned that, under these circumstances, the dialogue between the FRA and the railroad not proceed based only upon the narrow technical details of risk assessment. Instead, the dialogue should center around the extent to which the events that occurred involved unnecessary harm to employees or the public and require remedial action that is practical and cost effective. If the public is to be served, FRA should not be shackled by its own performance criteria, and
pro forma
compliance with risk assessment should not bar inquiry into whether, as a practical matter, systems “may be operated safely without unnecessary risk of personal injury.” No amount of research is likely to make risk assessment a pure science, and no amount of litigation over it will protect employees and the public from patent hazards identified after the fact. FRA is not reassured by the discussion that led

to this proposal that this concern is frivolous, and FRA will not proceed with a final rule in this proceeding until a way has been found to resolve it.

FRA invites comments specifically addressing any of the agency's concerns detailed in this proposal.

Application to Part 235: Risk Assessments and Material Modification of Systems

This set of regulatory proposals includes performance-based rules for new signal and train control systems (including subsystems and components) but does not alter part 235, which governs applications for discontinuance or material modification of a signal system. FRA believes that risk assessment techniques can be helpful in evaluating applications for modification or discontinuance of existing signal systems. However, FRA is not prepared at this time to be bound by risk assessment outcomes in evaluating these applications.

In enacting the Signal Inspection Act, the Congress both authorized FRA to require installation of signal systems and required that FRA review their removal or any reduction in their effectiveness. FRA has been reluctant to order new signal system installations, because it appears that the market functions reasonably well due to the natural constraints associated with the growth of rail traffic. Railroads continue to install traffic control systems where capacity requires it, and those investments provide efficiencies that benefit the health of the railroads while also enhancing safety over the long term, both directly and indirectly.

FRA has also been reluctant, however, to allow removal of signal systems where current travel levels benefit from the safety that they provide, even if the agency would not order installation of a new system under the same circumstances. Tools such as the CRAM II model and the ASCAP model should assist FRA in determining the circumstances under which signalization is helpful. However, FRA is not convinced that the precision those tools can provide will always exceed in quality the judgment of railroad safety professionals who are intimately familiar with the territory and operations, particularly as applied to matters of limited scale.

FRA has also been reluctant to allow, and in recent years has been steadfastly opposed to allowing, elimination of automatic cab signal (ACS) and automatic train control (ATC) functions—functions that directly address, to a considerable degree, the issues of collision avoidance and protection of roadway workers. Certainly risk assessment techniques will be useful in the future to analyze proposals to replace ACS/ATC systems with communication-based PTC alternatives. However, FRA would not expect to seriously entertain arguments, based upon elaborate risk analysis, that less certain safety strategies or modest declines in traffic would support removal of ACS/ATC systems.

B. How Does This Proposal Affect Locomotive Electronics and Train Control?

This rule is prepared against a background of rapid and significant change in locomotive design. This change has direct implications for the future of train control systems onboard locomotives.

In the past, train control functions and systems for control of normal locomotive operating functions have been kept separate. Train control apparatus has applied independent of the normal throttle and braking functions, which were traditionally accomplished by mechanical and pneumatic controls used by the locomotive engineer. Cab signals and ATC/ATS appliances have included a separate antenna for interfacing with the track circuit or inductive devices on the wayside. The power supply and control logic for train control have been separate from other locomotive functions, and cab signals have been displayed from a special-purpose unit. Penalty brake applications have been accomplished by direct operation of a valve that accomplishes a service reduction of brake pipe pressure, and the train control system also functions to “knock down” the locomotive's tractive power. In keeping with this physical and functional separation, train control systems on board a locomotive have been considered exclusively within Part 236, rather than the locomotive inspection requirements of part 229.

Onboard locomotives, braking and throttle functions have traditionally worked independently, with discrete mechanical and pneumatic controls. As electronic systems were initially introduced, controls remained separate and distinct. Until recently, electronic controls have been packaged incrementally by various vendors (e.g., speed sensor vendor, brake system vendor, locomotive manufacturer). In locomotives that employ this arrangement, control functions may be distributed among several processors using proprietary software.

During the 1990's locomotive manufacturers (“original equipment manufacturers” or “OEMs'') began to integrate discrete functions, tapping certain inputs or outputs of the proprietary systems for informational or control purposes. Most new locomotives are controlled by microprocessors that respond to operator commands while making numerous automatic adjustments to locomotive systems to ensure efficient operation. In lieu of individual gages, operating parameters (such as speed, brake pipe pressure, and amperage) are displayed to the engineer on a single electronic display. The AAR has established Locomotive System Integration (LSI) criteria to promote compatibility among systems and uniformity in the information displayed to the locomotive engineer.

Currently, manufacturers are deploying central processors that may “run” a variety of systems simultaneously in a multi-tasking environment. While “integration” has been largely functional in the past, including the common display, the control systems themselves may be unified in the future.

Locomotive manufacturers are preparing more capable electronic platforms to support locomotive and train control functions, but to date FRA has taken the position that train control functions should remain separate. Historically, and within the context of existing ACS/ATC systems, train control functions have been required to be carried out in a failsafe manner by “vital” systems. Locomotive electronic controls, while designed with a high degree of attention to safety, have thus far not been demonstrated to fail safely with a high degree of reliability, and in individual cases unsafe failures have occurred. In effect, electronic control of locomotive functions has arisen in recent years without regulation, and in some cases products have been deployed prior to adequate analysis and testing. As a result, locomotive engineers have expressed concern regarding the safety characteristics of certain electronic features. Despite the best efforts of OEMs and suppliers, in some cases engineers have been relegated to use of emergency brake valves in the face of blank screens and uncertain availability of normal control functions.

Very clearly, certain locomotive controls are highly safety-critical, and FRA is working with the OEMs to encourage adoption of formal safety methods in the design, verification and validation of locomotive systems. FRA is confident that, over the next few years, OEMs and their suppliers will succeed in improving the quality of safety-relevant locomotive electronic

systems. As that occurs, integration of train control functions with other on-board functions will be appropriate. Until that time, FRA believes that cab signal and train control functions, including innovative PTC technologies, should continue to operate independent of locomotive information and control systems. In the context of developing PTC projects, and with respect to application of required ACS/ATC systems on new locomotives, FRA will for the time being continue to insist upon separation of locomotive and train control functions (absent an affirmative showing by the OEM that essential functions are effectively isolated and implemented in a failsafe manner as required in part 236). However, both for today and the future, FRA sees value in use of the electronic display for cab signal and train control functions, if the generation of the relevant attributes of the display can be made failsafe (with the exception of the very low-probability possibility of a transient fault in the display itself).

FRA seeks comment on this issue and the circumstances under which the final rule should authorize or prohibit integration of locomotive control and train control functions. Should integration of these functions be allowed? If they are integrated, how should in-service failures of various kinds be handled (e.g., failure of one of two displays available to the engineer or failure of the conductor's display). If these functions are integrated, should the entire locomotive electronic system be subject to verification and validation under the new performance standards? If so, to what extent might train control functions be partitioned from other applications to simplify the problem, and in what way?

C. What Risk Assessment Methods Will Be Considered Adequate?

One of FRA's greater challenges concerning this proposed rule will be verification of compliance with the performance-based standard. The Standards Task Force has recommended an enforcement scheme under which railroads would conduct, when required, a risk assessment to show that the performance standard is met. In most cases, FRA envisions that the risk assessment will identify the assigned risk classes for the system, assign a numerical expression for each safety integrity level, specify a target failure rate, and identify the standards upon which the assessment and calculations were made. This information can be used as a basis to measure and identify the likelihood of a hazardous event and the potential for the system to function as intended. With this information, the railroad and FRA can confirm compliance with the performance standard.

The primary goal of the risk assessment required by this proposed rule is to give an objective measure of the levels of safety risk involved for comparison purposes. As such, FRA believes the focus of the risk assessment ought to be the determination of relative risk levels, rather than absolute risk levels. Most of the analytical techniques explored by the Standards Task Force analyzed relative risk levels much more effectively than they analyzed absolute risk levels. Thus, the proposed rule attempts to emphasize the determination of relative risk.

The Standards Task Force realized that risk assessments may be performed using a variety of methods, so they proposed creation of certain guidelines to be followed when conducting risk assessments. FRA feels these guidelines, captured in § 236.909(e) and Appendix B, adequately state the objectives and major considerations of any risk assessment it would expect to see submitted per subpart H. FRA also feels these guidelines allow sufficient flexibility in the conduct of risk assessments, yet provide sufficient uniformity by helping to ensure final results are presented in familiar units of measurement.

One of the major characteristics of a risk assessment is whether it is performed using qualitative methods or quantitative methods. The proposed rule would allow both quantitative and qualitative risk assessment methods to be used, as well as combinations of the two. FRA expects that qualitative methods should be used only where appropriate, and only when accompanied by an explanation as to why the particular risk cannot be fairly quantified. Initially, the Standards Task Force considered allowing only quantitative risk assessment methods to facilitate relative risk comparison. However, suppliers noted that certain risks, such as software coding errors, cannot be fairly or easily quantified, and that the industry practice is to assess such risks qualitatively. FRA invites comments addressing the extent to which qualitative risk assessment methods ought to be considered sufficient.

The Standards Task Force further recommended that railroads/suppliers not be limited in the type of risk assessments they should be allowed to perform to demonstrate compliance with the minimum performance standard. FRA feels that state of the art of risk assessment methods could potentially change more quickly than the regulatory process will allow, and not taking advantage of these innovations could slow the progress of implementation of safer signal and train control systems. Thus, FRA proposes that risk assessment methods not meeting the guidelines of this proposed rule be allowed, so long as it could be demonstrated to the FRA Associate Administrator for Safety that the risk assessment method used is suitable in the context of the particular product. FRA believes this determination is best left to the FRA Associate Administrator for Safety because the FRA would retain authority to ultimately prevent implementation of a system whose Product Safety Plan does not adequately demonstrate compliance with the performance standard under the proposed rule.

Regardless of the risk assessment method used, FRA prefers the same method to be used for both previous condition (base case) calculations and calculations of risk associated with the proposed product. FRA prefers similar if not identical methods to be used so that meaningful comparisons can be made.

However, the proposed rule does not mandate that identical methods be used in every case. FRA is aware that some types of risk are more amenable to measurement by using certain methods rather than others because of the type and amount of data available. For example, in almost all situations where advanced train control technology will be economically viable, safety risk data and accident histories will often be more abundant for the previous condition than for operation with the proposed product. The latter calculation will normally be based on supplier data about the product and modeling of how it is intended to be used on the railroad. Because FRA is interested in ensuring that each relative risk determination is accurate, the proposed rule does not outright mandate that the same assessment method be used. If a railroad does elect to use two different risk assessment methods, FRA will consider this as a factor for PSP approval (see § 236.915(g)). Also, in such cases, FRA will be more likely to require an independent third party review and assessment (see § 236.915(h)).

Section-by-Section Analysis

Section 209.11 Request for Confidential Treatment

FRA proposes an amendment to this section, as recommended by the Standards Task Force, to clarify existing procedures for requesting confidential treatment for documents provided to the

FRA in connection with the agency's enforcement activities. First, the section would be amended to indicate that the procedures governing requests for confidential treatment apply to documents provided to the FRA in connection with the agency's enforcement of both the railroad safety statutes and the railroad safety implementing regulations. Second, the section would be amended to clarify the definition of what activities constitute FRA enforcement activities. Under the revised definition, enforcement would include receipt by the FRA of documents required to be submitted by FRA regulations, and all documents received by the FRA in connection with FRA's investigative and compliance activities, in addition to the development of violation reports and recommendations for prosecution.

Section 234.275 Processor-Based Systems

Section 234.275 proposes standards for highway-rail grade crossing warning systems using new or novel technology or providing safety-critical data to any product governed by subpart H of part 236. Currently part 234 provides requirements for the maintenance, inspection, and testing of highway-rail grade crossing warning systems. In September 1994, FRA issued a final rule on part 234 (Grade Crossing Signal System Safety, 59 FR 50,086, Sep. 30, 1994), but the final rule did not address processor-based warning systems which are integrated with signal and train control systems. FRA feels it is necessary for these types of systems to be addressed in subpart H because of the potential for their integration or interaction with processor-based signal and train control systems. With the large number of processor-based warning systems currently installed at the nation's highway-rail grade crossings, however, it would be unrealistic to attempt to bring all of those within the scope of subpart H. The processor-based warning systems currently in use and meeting the maintenance, inspection, and testing requirements of part 234 do an admirable job of warning highway users. The Standards Task Force formed a team of its members to identify such items as PTC system data to be transmitted to and integrated with highway traffic control/information systems (future capability). See “Implementation of Positive Train Control Systems,” page viii (September 8, 1999). This focus captured the potential uses of Intelligent Transportation System (ITS) technology at highway-rail grade crossings. This proposed requirement identifies which processor-based highway-rail grade crossing warning systems are subject to the requirements of subpart H of part 236.

Paragraph (a) provides that relevant definitions of part 236, subpart H, apply to this section.

Paragraph (b) proposes a standard for whether a highway-rail grade crossing warning system must meet the requirements of subpart H. “New or novel technology” is defined in the third sentence of the paragraph. FRA envisions new or novel technology to include such technology as that incorporated in new designs which do not use conventional track circuits or that used in ITS, which utilize data provided through advanced signal and train control systems to warn motor vehicle drivers of approaching trains. FRA does not intend for new or novel technology to include any technology used in current systems (as of the effective date of this rule). FRA is considering tailoring this definition to more accurately reflect the intent of the Standards Task Force, which was to include only technology not previously recognized for use in applications subject to part 234.

Paragraph (c) proposes requirements for equipment subject to this section. These are additional requirements which must be included in the PSP.

Paragraph (d)(1) is proposed to confirm that this section in no way authorizes deviation from the requirements of the Manual for Uniform Traffic Control Devices (MUTCD). Current “wayside” warning devices are standardized by the MUTCD. The MUTCD sets forth the basic principles that govern the design and usage of traffic control devices for all streets and highways open to public travel regardless of type of class or the governmental agency having jurisdiction. Part VIII of the MUTCD applies to traffic control systems for highway-rail grade crossings. Traffic control systems for such crossings include all signs, signals, markings and illumination devices along highways approaching and at crossings. Traffic control systems are required to be consistent with the design and application of the standards contained within the MUTCD.

Section 236.0 Application

As a general matter, this proposed rule would apply to all railroads, with two exceptions. First, railroads which operate on track wholly separate from the general railroad system of transportation are excepted from all requirements of part 236. Second, rapid transit operations in an urban area which are not connected to the general railroad system of transportation would be unaffected by the requirements of part 236. FRA proposes this change in language solely to standardize the application of all of the federal regulations related to railroad safety. For additional information on the extent and exercise of FRA's safety jurisdiction, see 49 CFR part 209 appendix A as amended on July 10, 2000 (65 FR 42544).

Section 236.18 Software Management Control Plan

This section proposes a requirement for all railroads to adopt a software management control plan to assure that software used in processor-based signal and train control equipment in service is the version intended by the railroad to be in service at each location. Simply put, a software management control plan is an inventory of software at each equipment location. As a processor-based signal and train control system ages and experiences modifications (i.e., changing operating conditions or upgrades in hardware and software), the software management control plan should be updated accordingly, providing traceability to previous versions of software. One should always be able to determine from the software management control plan precisely what software is installed at each equipment location in the field. This proposed requirement would provide an audit trail to determine if the correct software is installed at the correct locations for all processor-based signal and train control systems on a railroad.

FRA proposes this requirement because for a considerable time after the introduction of processor-based equipment into signaling systems, components of such systems were not always handled responsibly. It was not unusual for railroad employees to carry in their clothing pockets printed circuit (PC) boards and the programmable memory devices (PROMs) which plug into those boards. When driving to equipment locations, sometimes remote, these employees would even recklessly place PC boards and PROMs in tool bins and tool boxes. When troubleshooting a piece of equipment, it was common practice to simply exchange the failed PC board with ones from the selection the employee had on hand until the device appeared to function as intended. The pulled board was often saved for the purpose that it might work in another device. For this and other reasons, in the Orders of Particular Applicability for processor-based train control systems on the Northeast Corridor (63 FR 39343, 52 FR 44510),

PROMs were required to be soldered in place in order to assure proper software versions were installed on locomotives.

With the proliferation of processor-based equipment and use of PROMs with both erasable and non-erasable memory, it is no longer practical to require the soldering of PROMs on PC boards. A software management plan will track the version of software which should be and is in use at all equipment locations on a signal and train control system. Therefore, a requirement for software management control plans would provide adequate assurance that processor-based equipment is programmed with the correct software version.

The inventory should identify, among other things, the software by version number. FRA would expect the software management control plan identify and document for each equipment location the executive or application software name, software version number, software revision number, date of software revision, and a description of cyclic redundancy check for verifying PROM contents. The Task Force had initially considered a requirement that railroads adopt configuration management plans, which would cover both software and hardware dealing with safety-critical aspects of processor-based signal and train control systems. Railroads expressed concern that such a requirement would be unduly burdensome since there is no current configuration management requirement in place, and that certainly simple one-for-one hardware changes need not be tracked. As a practical matter, FRA envisions a limited amount of hardware tracking as a necessary element of software management, since software can reside in portable hardware elements. FRA invites comments specifically addressing this issue.

There is currently no recognized industry standard for software management; however FRA is aware that other computerized systems on railroads such as accounting and communications systems use configuration management control principles. FRA believes that a requirement for software management control plans on signal and train control equipment will enhance the safety of these systems and ultimately provide other benefits to the railroad as well.

This proposed requirement holds railroads responsible for all changes to the software configuration of their products in use, including both changes resulting from maintenance and engineering control changes, which result from manufacturer modifications to the product. In FRA's view, both of these types of changes carry significant safety implications, and should be tracked by the railroad. FRA is aware that most maintenance changes involve replacement of PC boards or software on PROMs, and that changes such as replacement of resistors on PC boards are not normally made by the railroad, but rather the product manufacturer. FRA feels that it would be appropriate for the railroad to track changes no deeper than at the PROM software levels; however, it would be unrealistic and cumbersome to expect the railroad to document changes such as replacement of resistors on PC boards. FRA invites comments specifically addressing this issue.

It is also recognized that this requirement may unduly burden the railroads in situations where they receive inaccurate information from the product manufacturer concerning manufacturer modifications. This poses safety risks because a railroad relying on a manufacturer's statement certifying compatibility, for example, with another manufacturer's system may create a dangerous situation if in fact the two products are not compatible. FRA feels that the railroads should be entitled to rely on the manufacturers' product information since manufacturers obviously know much more about the specifics of their products. In essence, the proposed requirement would impose a strict liability standard on the railroads regardless of culpability. FRA invites comments addressing the issue of whether railroads and suppliers ought to share responsibility for the duty of maintaining proper software configuration, and if so, how such responsibility can be effectively delineated. FRA further invites comments concerning the scope of a product manufacturer's duty to provide accurate information concerning initial software configuration of its products and any engineering control changes.

Paragraph (a) discusses the proposed application of this requirement to all railroads and how it applies to railroads not in operation as of the effective date of this rule. The Standards Task Force intended for this requirement to apply to all systems which would be specifically excluded by the § 236.911 in subpart H. For subpart H products, configuration management for each product must be specified in the PSP and the Operations and Maintenance Manual, as required by §§ 236.907(a)(13) and 236.919(b). These specifications must comply with the railroad's RSPP.

Although the issue of allowance time for compliance was not covered by the Standards Task Force, FRA proposes a 24-month time period as sufficient. FRA welcomes comments specifically addressing this issue.

Paragraph (b) proposes a requirement for software management control plans, and further would require that the plan identify tests required by the system developer and/or the railroads in the event of replacement, modification, and disarrangement.

Section 236.110 Results of Tests

FRA proposes modification of existing § 236.110 to include record keeping requirements for processor-based signal and train control systems under part 236, subpart H and to make it consistent with current agency policy concerning record keeping. As modified, § 236.110 would incorporate in four paragraphs new language and language from current § 236.110.

Paragraph (a) outlines four primary changes. First, FRA proposes to add two new sections to the list of sections to which § 236.110 applies: §§ 236.911 and 236.917(a), both of which apply to processor-based equipment covered by subpart H. Currently, there is no established safety record or performance history for these new types of systems.

Second, paragraph (a) proposes to allow for electronic record keeping. In conjunction with FRA's policy of encouraging such methods where available and appropriate, FRA would like to allow for railroads to be able to avail themselves of this method. FRA proposes that carriers adopting electronic means to record results of tests first obtain FRA's approval through an application process. Requiring FRA approval will establish a process whereby FRA can ensure all the proper information (prescribed in proposed paragraph (a)) is recorded. FRA will also be able to determine where and how the electronic records are available for inspection. FRA notes that if tests are performed by Automated Test Equipment (ATE) the test equipment shall be identified by a unique number, and the test record must reflect that number.

Third, FRA offers changes to § 236.110 to make clear that records filed with a railroad supervisory officer with jurisdiction are subject to inspection and replication by FRA. Railroad supervisory officer is intended to mean an assistant signal supervisor, signal supervisor, or any responsible divisional officer. If a railroad receives approval for electronic record keeping, the railroad shall inform FRA how and where the electronic records will be available for inspection during normal business hours. However, in the case of life cycle records required by proposed § 236.110(c)(1), the railroad shall inform

FRA of the office location(s) where these life cycle records will be kept. If electronic recordkeeping (in accordance with paragraph (e)) is not used for train control test records, then these records must be kept at the locomotive office nearest the test point location(s).

Fourth, paragraph (a) corrects a misprint in current § 236.110, concerning the list of sections to which it applies. The proposed paragraph lists in proper numerical order the sections to which § 236.110 applies.

Paragraphs (b), (c), and (d) provide requirements for how long such records specified in paragraph (a) are to be maintained. Paragraph (b) simply restates a current requirement of § 236.110 (fourth sentence).

Paragraph (c) proposes a requirement to specify the length of time records made in compliance with § 236.917(a) are to be kept. Paragraph (c)(1) proposes a requirement for all railroads to maintain records for results of tests conducted when a processor-based signal or train control system is installed or modified. These records must be retained for the life cycle of the equipment. FRA feels tracking modifications to processor-based equipment is necessary, because such changes, especially those concerning software, are not often readily apparent, yet may lead to hazardous conditions. Whenever processor-based equipment or software is modified or revised, it must be tested to ensure it is still functioning as intended. FRA believes these records will also provide valuable information to the railroad and manufacturer pertaining to the reliability of the equipment.

Paragraph (c)(2) deals with maintenance and repair records. For the following two reasons, the Standards Task Force recommended that these records be kept for one year, or until the next record is made. First, a subset of these records (those involving hazardous events) will be tracked in the product's hazard log (see § 236.907(a)(6)). Second, many repairs to signal and train control equipment are not performed by the railroad, but rather by contractors. It would be burdensome for repair records to be tracked by the railroad for the lifetime of the product when different contractors might be performing the actual repair work over the product's lifetime. Thus, a requirement for lifetime record retention of test records pertaining to product repairs would be substantially duplicative and burdensome. However, the Task Force noted that PSPs should address issues of railroad signal employee access to repair records and hazard logs for products used throughout the railroad, as these may contain important information for performance of their duties.

Paragraph (d) simply restates a current requirement of § 236.110 (fifth sentence).

Paragraph (e) proposes to allow electronic recordkeeping in lieu of preprinted paper forms.

Section 236.787a. Railroad

FRA proposes this definition to aid in standardizing the application provisions of its regulations.
See
also 49 CFR 238.5.

Section 236.901 Purpose and Scope

This section describes both the purpose and the scope of subpart H.

Section 236.903 Definitions

The term “component” is intended to signify an identifiable part of a larger program or construction. A component usually provides a particular function or group of related functions. By proposing such a definition, FRA does not intend to overburden railroads or suppliers by requiring safety performance data and analysis on the least significant of these identifiable parts. Rather, FRA encourages railroads to take advantage of supplier data, which is normally readily available for off-the-shelf components. FRA assumes that railroads and suppliers will use discretion to appropriately define components at levels not quite as simple as a resistor, but also not quite so complex that they could not be readily replaced. For instance, FRA envisions components defined no more specifically than at the printed circuit board level, or E-PROM level.

The term “executive software” is intended to encompass that software which affects the overall structure of a signal or train control system and the nature of the interfaces between its various subsystems and components. Executive software remains the same from installation to installation; the design is not changed and it is not recompiled.

The term “full automatic operation” is defined per recommendation from the Standards Task Force. This definition was crafted with respect to the railroad industry, which involves both freight and passenger operations. Other definitions come from the transit industry and involve such nuances as door control. The definition captures the notion that locomotive engineers/operators may act as both passive monitors and active controllers in an full automatic operating mode.

This proposed rule is not designed to address all of the various safety issues which would accompany full automatic operation. Indeed, FRA would anticipate the need for further rulemaking to address the wide range of issues that would be presented should automatic operation be seriously contemplated. However, insofar as skills maintenance of the operator is concerned, the proposed rule offers standards in § 236.927.

The term “human factors” refers to the limitations in human performance, abilities, and characteristics that designers should consider when designing subpart H products. FRA believes that designers can improve the safety of products by considering human factors as early as possible in the design process. Design that does not account for human factors, however, can degrade safety.

The term “human-machine interface” refers to the way an operator interacts with the product. FRA feels designers who incorporate human factors design principles in a human-machine interface can increase system safety and performance.

The term “Mean Time To Hazardous Event” is used to capture the parameter widely accepted in the safety/reliability engineering discipline as a scientifically-based prediction of the measure of time likely to pass before the occurrence of a hazardous event. Railroads have indicated objection to the use of the term “average” or “expected” in the definition of MTTHE. FRA invites comments addressing this issue specifically.

The term “new or next-generation train control system” is intended to capture the notion of a train control system utilizing a relatively new technology or new generation of technology, not currently in use in revenue service. Under this definition, a significant change in the way signal and train control systems work, such as that brought about by Locomotive Speed Limiter (LSL), could be trigger classification as a new or next-generation train control system. Other factors, such as the relative maturity of the product brought to market, may be relevant to this determination.

The term “predefined change” is intended to signify any change likely to have an effect on the risk assessment for the product. FRA imagines that predefined changes will include: additions, removals, or other changes in hardware, software, or firmware to safety-critical products, application software, or physical configuration description data, under circumstances capable of being anticipated when the initial PSP is developed. FRA is considering amending the definition of predefined change to includes both

changes made directly to the product and changes to how the product is used. FRA urges parties developing product PSPs to consider all likely configurations for the product, and include such considerations in the risk assessment. This will reduce the likelihood of being required to file a PSP amendment at a later date when the railroad wishes to slightly reconfigure their product or make a slight change to it.

The term “preliminary hazard analysis” is intended to signify the process used to develop a comprehensive listing of all safety-enhancing or safety-preserving functions which safety-critical products will perform. This listing should address the requirements currently used to provide for safety of train movements in the Rules, Standards & Instructions (RS&I) (part 236). It should also be consistent with those requirements derived from laws of physics, such as minimum required braking distances, and provide guidance as to how such requirements should be met.

The term “product” is proposed to encompass all signal or train control equipment which is processor-based, including: (i) A processor-based component of a signal or train control system, and (ii) a processor-based subsystem of a signal or train control system, or the system itself, if processor-based. A processor-based subsystem is intended to signify a signal or train control system's subsystem which contains a processor-based component. A processor-based signal or train control system is intended to mean a signal or train control system which contains a processor-based component.

For issues related to the definition of “risk assessment,” please see major issue (c)-Risk Assessment Methods.

The term “safety-critical” is intended to apply to any function which must be correctly performed in order to avoid causing a hazardous condition to equipment or personnel. If not performing correctly, a safety-critical system, subsystem, or component could cause a hazardous condition or permit the occurrence of a hazardous condition which it was designed to prevent. An example of the latter would be an “overlay” system that does not constitute any part of the method of operation, but maintains safe system operation should any one of the safety-critical functions be omitted or not performed correctly (e.g., human error).

The term “subsystem” is intended to mean, for purposes of this rule, any defined portion of a system. Subsystems will normally have distinct functions, and may be constitute systems themselves.

The term “system” is intended to mean a composite of people, procedures and equipment which are integrated to control signals or train movement within a railroad. (Adapted from Roland, Harold E. and Moriarty, Brian, “System Safety Engineering and Management,” Second Edition, John Wiley and Sons, Inc., 1990, p. 6.)

The term “system safety precedence” is intended to capture the concept of a priority of means for hazard elimination or mitigation, as stated in Military Standard 882C, “System Safety Program Requirements” (U.S. Department of Defense; January 18, 1993).

The term “validation” is slightly modified from the IEEE definition to incorporate the notion that validation procedures do not end with the end of the development cycle. Validation can be performed at any stage of a product's life cycle, including and especially after modifications are made to it. One supplier indicated that this proposed definition ought to be modified to exclude references to what stages in a product's life cycle validation is performed. Commenters are invited to address this issue specifically.

Section 236.905 Railroad Safety Program Plan (RSPP)

The system approach to safety is used pervasively in a variety of industries to reduce the risk of accidents and injuries. FRA has discussed the need for this approach to safety in three recent rulemakings: FOX High Speed Rail Safety Standards, 62 FR 65478, Dec. 12, 1997; Passenger Train Emergency Preparedness, 63 FR 24630, May 4, 1998; and Passenger Equipment Safety Standards, 64 FR 25540, May 12, 1999. System safety means the application of design, operating, technical, and management techniques and principles throughout the life cycle of a system to reduce hazards and unsafe conditions to the lowest level possible, through the most effective use of available resources. The system safety approach requires an organization to identify and evaluate safety hazards that exist in any portion of the organization's “system,” including those caused by interrelationships between various subsystems or components of that system. The organization then creates a plan designed to eliminate or mitigate those hazards. Where possible, the development of a system safety plan precedes the design, implementation, and operation of the system, so that potential risks are eliminated at the earliest possible opportunity. System safety plans are viewed as living documents, which should be updated as circumstances or safety priorities change or new information becomes available.

This section proposes that railroads implement FRA-approved system safety plans, enforce them, and update them as necessary. In this process, FRA proposes that the railroad implement their RSPP to identify and manage safety risks, and generate data for use in making safety decisions. Based on the philosophy of system safety planning, FRA believes that initiating this process prior to design and implementation of products covered by subpart H is necessary for development of safety-critical processor-based signal and train control systems.

Paragraph (a) would require the railroad to adopt an RSPP. FRA envisions that the RSPP will be a living document that evolves as new information and knowledge become available. Due to the critical role that the RSPP plays in this proposed rule, FRA proposes that the railroad submit their initial plan for FRA review and approval prior to implementation of safety-critical products. Since the development of many safety-critical features in products will be guided by the RSPP, FRA believes that its review and approval is essential. FRA feels this role is a logical and necessary outgrowth of its responsibility to promulgate clear, enforceable, and effective safety standards. This paragraph also requires the railroad to submit their initial RSPP to FRA. FRA believes that the RSPP must be used as a guide in the earliest conceptual stages of a project.

Paragraph (b) proposes that the RSPP address minimum requirements for development of products. It provides minimum requirements which the RSPP must address. FRA intends the plan to be a formal step-by-step process which covers: identification of all safety requirements that govern the operation of a system; evaluation of the total system to identify known or potential safety hazards that may arise over the life cycle of the system; identification of all safety issues during the design phase of the process; elimination or reduction of the risk posed by the hazards identified; resolution of safety issues presented; development of a process to track progress; and development of a program of testing and analysis to demonstrate that safety requirements are met. These minimum requirements are addressed in paragraphs (b)(1) through (b)(4).

Paragraph (b)(1) proposes a requirement that the RSPP provide a detailed description of the tasks to be completed during the preliminary hazard analysis for every safety-critical

product developed for use on the railroad. Paragraphs (b)(1)(i) through (b)(1)(iv) list several types of tasks which must be included in the RSPP. Railroads have indicated that requirement (iv), the identification of the safety assessment process, appears to duplicate (ii), the complete description of risk assessment procedures. FRA intends the risk assessment to be a measurement tool, used to benchmark safety levels and hopefully to provide valuable safety insight to designers. FRA views the safety assessment process as a more comprehensive process in which design for safety concerns are effectively identified and addressed at all stages of product development. FRA welcomes further comments concerning the railroad's claim and this distinction.

Paragraph (b)(2) discusses how the RSPP identifies validation and verification methods for the initial design/development process and future changes, including any standards to be complied with in the validation and verification process. The objective is that railroad create and maintain documentation which will facilitate an independent third party assessment, if required (see § 236.915(h)). FRA believes this process will also help to refine and standardize validation and verification processes for each railroad.

Paragraph (b)(3) proposes a requirement that the RSPP contain a description of the process used during product development to identify and consider the human-machine interfaces (HMIs) which affect safety. The proposed requirements set forth in this paragraph and in appendix E attempt to mandate design consideration of, among other concerns, sound ergonomic design practices for cab layout in order to minimize the risk of human error, attention loss, and operator fatigue. FRA believes it is necessary for railroads/product manufacturers to be able to demonstrate how their human factors design requirements are developed and that they are developed at an early stage in the product development process.

Paragraph (b)(4) discusses how the RSPP identifies configuration management requirements for the configuration of products subject to subpart H. The Standards Task Force felt this requirement was necessary to help railroads maintain consistency in the configuration management of the products they use.

Paragraph (c) describes the proposed initial review and approval procedures FRA will utilize when considering each railroad's RSPP. Paragraph (c)(1) indicates that the petition must be delivered to the Docket Clerk, Office of Chief Counsel, for action by the FRA Associate Administrator for Safety. Paragraph (c)(2) establishes the timing of the petition process. FRA normally responds in some fashion within 180 days with one of the responses listed (grant the petition, deny the petition, or request additional information). However, there may be circumstances in which FRA is unable to respond as planned. Consequently, paragraph (c)(3) indicates that inaction by FRA within the 180-day period means the petition will remain pending. The petition is not approved until the railroad receives an affirmative grant from FRA. Railroad members of the Standards Task Force suggested that FRA should notify them if an extension to the 180-day period will be needed, and provide the reasons therefore. FRA invites comments addressing FRA's handling of RSPP petitions beyond 180 days after filing. Paragraph (c)(4) proposes that FRA be able to reopen consideration for any previously-approved petition for cause. This will help ensure that FRA has the ability to preempt problems erupting as a result of widely disparate safety priorities being implemented throughout the industry.

Paragraph (d) proposes requirements for how and when RSPPs can be modified. First, FRA believes railroads can and should modify their RSPPs at any time. However, when RSPP modifications related to safety-critical PSP requirements are involved, FRA feels its approval is necessary. Paragraph (d)(1) proposes a requirement that railroads obtain FRA approval in these cases. In any other case, the railroad would be able to implement the modification without FRA approval. Paragraph (d)(2) proposes that procedures for obtaining FRA approval of RSPP modifications are the same for those used to obtain initial FRA approval, with the added requirements that the petition identify the proposed modifications, the reason for the modifications, and the effect of the modifications on safety. FRA notes that it may not be necessary to remit copies of the entire RSPP.

Section 236.907 Product Safety Plan (PSP)

This section describes the contents of the Product Safety Plan (PSP) that must be developed to govern each product. The provisions of this section require each PSP to include all the elements and practices listed in this section to assure these products are developed consistent with generally-accepted principles and risk-oriented proof of safety methods surrounding this technology. Further, each PSP must include acceptable procedures for the implementation, testing, and maintenance of the product.

FRA's existing regulations covering signal and train control systems do not include requirements of such detail since they are based on minimum design standards of long standing application that are recognized as appropriate to achieve the expected level of performance. As a result of the industry's desire to move to “performance-based standards” for signal and train control systems, FRA believes it is necessary to include the provisions contained in this section in order to assure safety of railroad employees, the public, and the movement of trains. In addition, FRA must ensure that key elements in the development of products correlate with the concepts of proven standards for existing signal and train control systems. FRA seeks comments on whether the elements contained in this section are adequate or whether there are other requirements that should be included to assure safety.

Paragraph (a)(1) would require the PSP include system specifications that describe the overall product and identify each component and its physical relationship in the system. FRA will not dictate a specific product architecture but will examine each to fully understand how various parts relate to one another within a system. Safety-critical functions in particular will be reviewed to determine whether they are designed on the failsafe principle. FRA believes this provision is an important element that can be applied to determine whether safety is maximized and maintainability can be achieved. Railroads have expressed concern over the level of detail required in describing the product. Commenters are invited to address this issue.

Paragraph (a)(2) would require a description of the operation where the product will be used. FRA is essentially attempting to determine the type of operation on which the product is designed to be used. One signal system supplier noted that this paragraph may not be applicable to products which are independent of some or all of the railroad operation characteristics described in this paragraph. FRA invites comments addressing this issue.

Paragraph (a)(3) requires the PSP to include a concepts of operations document containing a description of the product functional characteristics and how various components within the system are controlled. FRA believes that this provision along with that contained in paragraph (a)(1) above will assist in a thorough understanding of the

product. FRA will use this information to review the product for completeness of design for safety by comparing the functionalities with those contained in standards for existing signal and train control systems. While FRA will not prescribe standards for product design, FRA would require that the applicant compare the concepts contained in existing standards to the operational concepts, functionalities, and control contemplated for the product. For example, FRA requirements prescribe that where a track relay is de-energized, a switch or derail is improperly lined, a rail is removed, or a control circuit is opened, each signal governing movements into a block occupied by a train, locomotive, or car must display its most restrictive aspect for the safety of train operations. FRA intends to apply the same concept, among others, when reviewing PSPs to assure such minimum safety requirements exist.

Paragraph (a)(4) proposes that the PSP include a safety requirements document that identifies and describes each safety-critical function of the product. FRA intends to use this information to determine that appropriate safety concepts have been incorporated into the proposed product. For example, existing regulations require that when a route has been cleared for a train movement it cannot be changed until the governing signal has been caused to display its most restrictive indication and a predetermined time interval has expired where time locking is used or where a train is in approach to the location where approach locking is used. FRA will apply this concept, among others, to determine whether all the safety-critical functions are included. Where such functionalities are not clearly determined to exist as a result of technology development, FRA will expect the reasoning to be stated and justification provided how that technology provides equivalent or greater safety. Where FRA identifies a void in safety-critical functions, FRA will expect remedial action prior to use of the system. Interested parties are asked to comment on the adequacy of this process for preserving railroad safety.

Paragraph (a)(5) would require the PSP to contain a document demonstrating that the product architecture satisfies the safety requirements. The product architecture is expected to cover both hardware and software aspects which identify the protection developed against random hardware faults and systematic errors. Further, the document should identify the extent to which the architecture is fault tolerant. This provision may be included in the requirements of paragraph (a)(1).

Paragraph (a)(6) proposes that a hazard log be included in the PSP. This log consists of a comprehensive description of all hazards to be addressed during the life cycle of the product, including maximum threshold limits for each hazard (for unidentified hazards, the threshold shall be exceeded at one occurrence). The hazard log addresses safety-relevant hazards, or incidents/failures which affect the safety and risk assumptions of the product. Safety-relevant hazards include events such as false proceed signal indications and false restrictive signal indications. If false restrictive signal indications happen on any type of frequency, they could cause train crew members or other users (roadway workers, dispatchers, etc.) to develop a lackadaisical attitude towards complying with signal indications or instructions from the product, creating human factors problems. Incidents in which stop indications are inappropriately displayed may also necessitate sudden brake applications that may involve risk of derailment due to in-train forces. Other unsafe or wrong-side failures which affect the safety of the product will be recorded on the hazard log. The intent of this paragraph is to identify all possible safety-relevant hazards which would have a negative effect on the safety of the product. Right-side failures, or product failures which have no adverse effect on the safety the product (i.e., do not result in a hazard) would not be required to be recorded on the hazard log.

Paragraph (a)(7) would require that a risk assessment be included in the PSP. See major issue (c)-Risk Assessment Methods. FRA will use this information as a basis to confirm compliance with the minimum performance standard.

Paragraph (a)(8) proposes that a hazard mitigation analysis be included in the PSP. The hazard mitigation analysis must identify the techniques used to investigate the consequences of various hazards and list all hazards addressed in the system hardware and software including failure mode, possible cause, effect of failure, and remedial actions. A safety-critical system must satisfy certain specific safety requirements. Leveson, Nancy G., “Safeware: System Safety and Computers,” Addison-Wesley Publishing Company, 1995. To determine if these requirements are satisfied, the safety assessor must review and assess the results of the following tasks:

1. Hazards associated with the system have been comprehensively identified.

2. Hazards have been appropriately categorized according to risk (likelihood and severity).

3. Appropriate techniques for mitigating the hazards have been identified.

4. Hazard mitigation techniques have been effectively applied.

FRA does not expect that the safety assessment will prove absolutely that a product is safe. However, the safety assessment should provide evidence that risks associated with the product have been carefully considered and that steps have been taken to eliminate or mitigate them. Hazards associated with product use need to be identified, with particular focus on those hazards found to be have significant safety effects. Then, the designer must take steps to remove them or mitigate their effects. Hazard analysis methods are employed to identify, eliminate and mitigate hazards. Under certain circumstances, these methods will be required to be reviewed by an independent third party for FRA approval.

Paragraph (a)(9) would also require that the PSP address safety verification and validation procedures. FRA believes verification and validation for safety are vital parts of the development of products and, in certain cases, should be performed by a third party. Verification and validation requires forward planning and, consequently, the PSP should identify the test planning at each stage of development and the levels of rigor applied during the testing process. FRA will use this information to assure the adequacy and coverage of the tests are appropriate.

Paragraph (a)(10) would require the PSP to include the results of the safety assessment process by analysis that identifies each potential hazard and an evaluation of the events leading to the hazard; identification of safety-critical subsystems; the safety integrity level of each safety-critical subsystem; design of each safety-critical subsystem; results of a safety integrity analysis to assess the safety integrity level achieved by the safety-critical subsystems; and ensure from the analysis that the safety integrity levels have been achieved. FRA expects the safety assessment process to be clearly stated and thorough according to the complexity of the product. FRA realizes that paragraphs (a)(9) and (a)(10) may overlap in terms of requirements, and is considering consolidation of the concepts required in these two paragraphs.

Paragraph (a)(11) would require a human factors analysis which addresses

all human-machine interfaces (HMI's) and all product functions to be performed by humans to enhance or preserve safety. FRA expects this analysis to place special emphasis on human factors coverage of safety-critical hazards including the consequences of human failure to perform. Each HMI is to be addressed including the basis of assumptions used for selecting each such interface, its effect upon safety and identification of potential hazards associated with each interface. Where more than one employee is expected to perform duties dependent upon the output of, or input to, the HMI, the analysis must address the consequences of human failure to perform singly or in multiple. FRA uses this information to determine the HMI's effect upon the safety of railroad operations. The human factors analysis must address all criteria listed in Appendix E, unless approval is obtained from the Associate Administrator for Safety to use other equally suitable criteria. The Standards Task Force felt this flexibility is necessary for designers to have.

Paragraph (a)(12) would require the railroad to include in its PSP the training, qualification, and designation program for workers who perform inspection, testing, and maintenance tasks involving the product. FRA believes many benefits accrue from the investment in comprehensive training programs which, among other things, are fundamental to creating a safe workforce. Effective training programs can result in fewer instances of human casualties and defective equipment, leading to increased operating efficiencies, less troubleshooting, and decreased costs. FRA expects any training program to include employees, supervisors and contractors engaged in railroad operations, installation, repair, modification, testing, or maintenance of equipment and structures associated with the product.

Paragraph (a)(13) would require the PSP to identify specific procedures and test equipment necessary to ensure the safe operation, installation, repair, modification and testing of the product. Requirements for operation of the system must be succinct in every respect. The procedures must be specific about the methodology to be employed for each test to be performed that is required for installation, repair, or modification including documenting the results thereof. FRA will review and compare the repair and test procedures for adequacy against existing similar requirements prescribed for signal and train control systems. FRA will use this information to ascertain the product will be properly installed, maintained and tested.

Paragraph (a)(14) provides that products may be so designed that existing requirements contained in part 236, subparts A, B, C, D, E, and F are not applicable. In this event, the PSP must identify each pertinent requirement considered to be inapplicable, fully describe the alternative method used that equates to that requirement and explain how the alternative method fulfills or exceeds the provisions of the requirement. FRA notes that certain sections of part 236 may always be applicable to subpart H products. For example, § 236.0 p

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Source: Frix Law Library, https://www.frixlaw.com/law-library/documents/fr%3A01-19428. Public record. Not legal advice.