Locomotive Idling, Air Quality, and Blocked Crossings

Updated March 4, 2022

Locomotive Idling, Air Quality, and Blocked Crossings

When a train is not moving but its engines are running, it

can present risks and disruptions for the surrounding

community. Locomotives emit fuel exhaust that degrades

air quality and generates noise and vibrations. If the idling

train is stopped at a highway-rail grade crossing, local road

transportation could be significantly impacted, especially if

the nearest open railroad crossing is not close by. This

could create serious conditions if first responders are unable

to reach emergencies on the other side of the tracks.

Why Do Locomotives Idle?

Train engines generate thousands of horsepower and take

an hour or more to warm up before they can start pulling

rail cars. This is one reason there is reluctance to turn them

off. Also, particularly relevant for a locomotive attached to

a train, the brakes on the cars in the train do not work

without power. The locomotive must run to keep the air

pressure brakes on a train applied (the equivalent of

keeping a car in park). In temperatures below 40 degrees

Fahrenheit, the engine has to be kept warm for engine fluids

to work properly, as antifreeze cannot be used in

locomotive engines. Engines are also kept running to

provide air conditioning or heat for the crew, which may be

aboard even if the train is idling in a yard.

Why Do Trains Block Crossings?

When trains are moving at different speeds or in opposite

directions along a single-track rail line, one train will

usually have to wait on a side track or on the nearest twotrack segment until the other train has passed; if a road

crosses these tracks, the crossing will be obstructed until it

is safe for the train to proceed. In many cases, these waits

are planned and meant to be brief, but unforeseen delays

due to an oncoming or passing train can mean a stationary

train must remain in one place for an extended period.

Railroad crews, bound by hours-of-service limits, may not

be permitted to move the train, which then must wait until a

fresh crew can relieve them. Railroads try to schedule crew

changes in convenient locations, but service disruptions

occasionally make this impossible, forcing trains to stop

midway through a journey. Train stoppages are also

sometimes caused by mechanical failures.

Selected Recent Blocked Crossing Incidents

There are no national statistics on the frequency or severity

of blocked crossings, but recent incidents have received

media coverage:

 November 2021: a Norfolk Southern train blocked

several crossings in the West End neighborhood of

Birmingham, AL, for six days for unspecified reasons.

 June 2018: a Canadian National Railway (CN) train

broke down in the town of Barrington, IL, blocking all

four railroad crossings in the town for nearly an hour.

Ambulances transporting victims of a highway collision

were delayed in reaching the hospital. (Their injuries

were non-life-threatening.)

 April 2017: Senator Charles Schumer and then-Ulster

County Executive Michael Hein called on CSX to

resolve issues of trains idling at crossings in Kingston,

NY, which cuts off certain businesses from the rest of

the city entirely if they are located on dead-end streets.

Possible Responses to Locomotive Idling

Technology to Reduce Idling Noise/Emissions

The Environmental Protection Agency (EPA) has the

authority to regulate locomotive engine noise under the

Noise Control Act (42 U.S.C. §4916) and limit emissions

under the Clean Air Act (42 U.S.C. §7547). In a 2008

rulemaking (73 Federal Register 37096), EPA set stricter

emissions requirements for locomotive engines built or

remanufactured after 2012. It also required new

locomotives to be equipped with an automatic engine

start/stop system (AESS) that will shut down the engine

after 30 minutes of idling.

Once a train has been idle for over four hours, or if any cars

were removed or added while stopped, regulations require

crew to perform an air brake test prior to proceeding to the

next destination, a process that can take several minutes.

A second device, called an auxiliary power unit (APU), is a

small engine that can keep the locomotive’s main engine

warm, the batteries charged, and the brakes applied and

therefore allow the main engine to be turned off without

endangering the crew or the equipment. An AESS can be

programmed to trigger an APU automatically, without

requiring a rail worker to activate the locomotive on/off

switch. EPA opted not to require the use of APUs in the

2008 rulemaking. However, the emission cap regulations

offer a fairly strong incentive to install them (40 C.F.R.

92.132(a)(4)).

Freight trains can reach lengths of two miles, meaning it

can take several minutes to completely pass a crossing even

when rail traffic is moving. Where equipped, warning lights

or gates will engage some time before a train reaches a

crossing and will remain engaged for some time after a train

has passed, somewhat prolonging the traffic obstruction.

EPA does not have authority under the Clean Air Act to

require APUs or AESSs to be installed on existing

locomotives. To require railroads to install idle reduction

equipment on all existing locomotives, which typically have

service lives of 40 years, it would be necessary to either

enact freestanding legislation or amend the Clean Air Act.

https://crsreports.congress.gov

Locomotive Idling, Air Quality, and Blocked Crossings

Surface Transportation Board Remedies

The Surface Transportation Board (STB) reviews the

construction of new rail lines and transactions involving

existing lines. STB can impose environmental mitigation

measures, including those related to locomotive idling, as

part of this review process. For instance, when CN acquired

the so-called “J” Line around Chicago in 2008, STB

recognized that a moderately used shortline railroad would

become a heavily used main line track. STB, after a review

from its Office of Environmental Analysis, required CN to

take a number of measures to mitigate the adverse impacts

of increased train traffic on local communities. These

included

 construction of two road overpasses to eliminate

blocked crossings at heavily trafficked locations;

 accelerated acquisition of new locomotives that would

meet EPA emissions requirements for idling reduction

systems and new procedures to shut down locomotives

when not in use and when temperatures are above 40

degrees; and

 measures to keep railroad noise below a certain level for

nearby residents by constructing berms or installing

vegetation along the tracks.

Possible Responses to Blocked Crossings

2006 Blocked Crossings Study

Under a 2005 law, the Secretary of Transportation was

tasked with undertaking a study of the impact of blocked

highway-railroad grade crossings on emergency responders.

The final report, published in August 2006 by the Federal

Railroad Administration (FRA), noted that there is no

uniform national data collected on blocked crossings or on

emergency responder delays.

The report recommended forming close relationships

between the railroad and the community so that each may

be made aware of the other’s concerns. In particular, if the

railroad is aware of the locations of critical public safety

facilities, such as fire and ambulance stations, it may be

able to adjust the location at which trains stop in order to

ensure a nearby grade crossing is not blocked. There are

some actions railroad companies can take in order to

minimize time spent at crossings, including shortening

trains or building additional infrastructure. However, the

general tendency has been for railroads to run longer trains

for economic reasons, which may lead to lengthier delays at

grade crossings and more blocked crossings when a train is

stopped. Railroads can also adopt a policy of creating a gap

in a stopped train so as not to block a crossing, though the

process of creating the gap is time-consuming and would

require the crossing to be closed for that time.

FRA launched a website to collect blocked crossing

information from the public on a voluntary basis in 2019.

The Infrastructure Investment and Jobs Act of 2021 (IIJA,

P.L. 117-58) directs FRA to establish a blocked crossing

portal to collect and analyze blocked crossing data for a

period of three years. An earlier proposal for IIJA passed by

the House (H.R. 3684) contained measures, first introduced

in the Don’t Block Our Communities Act (D-BLOC, H.R.

3698), creating permanent data collection requirements for

railroads and the U.S. Department of Transportation (DOT),

but these were not enacted.

State Laws Regarding Blocked Crossings

There are no federal laws or regulations specifically

concerning highway-rail crossings blocked by trains.

According to a 2013 report compiled by FRA and

subsequent research conducted by CRS, 40 states and the

District of Columbia have laws in effect regarding

obstructed crossings. Many of these set a time limit on

trains to occupy crossings, ranging from as little as five

minutes to as much as 20 minutes. Other states do not

impose a statewide time limit but shield railroad employees

who block crossings based on orders from their supervisors.

However, state and federal courts have generally found that

these laws are preempted by one or more federal laws,

rendering them unenforceable. The Federal Railway Safety

Act of 1970 grants states the ability to enact their own rail

safety laws only if neither DOT nor the Department of

Homeland Security has issued regulations “covering the

subject matter of” the state law. Moreover, the Interstate

Commerce Commission Termination Act of 1995 further

restricts states from enacting laws that regulate rail

transportation. Railroad companies have successfully

argued in court that laws setting time limits at crossings are

functionally the same as regulating railroad business

practices such as train length and speed or infrastructure

construction, which states are not permitted to do.

The D-BLOC bill would have established a federal 10minute time limit for blocked crossings (with exceptions),

subject to civil penalties. These measures were passed by

the House but not retained for final passage within IIJA.

Grade Crossing Improvements

One effective but expensive way to resolve the issue of

blocked crossings is to construct grade-separated

over/underpasses so that rail traffic does not interfere with

road traffic. The 2015 surface transportation law, the FAST

Act, added “projects at grade crossings to eliminate hazards

posed by blocked grade crossings due to idling trains” in

the list of approved uses for the “Section 130” highway-rail

crossing safety program, which receives over $200 million

per year. These funds are then allocated to states by a

formula that slightly favors states with a disproportionately

large share of public grade crossings.

Certain grade separation projects are also an eligible use of

funds from the Rebuilding American Infrastructure with

Sustainability and Equity discretionary grant program,

known as RAISE (formerly TIGER and BUILD), and from

the Consolidated Railroad Infrastructure and Safety

Improvement program, both administered by DOT. In IIJA,

in addition to funding these programs, Congress created and

funded a new railroad crossing elimination grant program

specifically intended to eliminate highway-rail grade

crossings that are frequently blocked by trains.

Ben Goldman, Analyst in Transportation Policy

https://crsreports.congress.gov

IF10978

Locomotive Idling, Air Quality, and Blocked Crossings

Disclaimer

This document was prepared by the Congressional Research Service (CRS). CRS serves as nonpartisan shared staff to

congressional committees and Members of Congress. It operates solely at the behest of and under the direction of Congress.

Information in a CRS Report should not be relied upon for purposes other than public understanding of information that has

been provided by CRS to Members of Congress in connection with CRS’s institutional role. CRS Reports, as a work of the

United States Government, are not subject to copyright protection in the United States. Any CRS Report may be

reproduced and distributed in its entirety without permission from CRS. However, as a CRS Report may include

copyrighted images or material from a third party, you may need to obtain the permission of the copyright holder if you

wish to copy or otherwise use copyrighted material.

https://crsreports.congress.gov | IF10978 · VERSION 4 · UPDATED