Document ID: FRA-2009-0031-0228
Agency: fra
Document Type: Notice
Title: Positive Train Control Interface Design Issue with Locomotive and Cab Car Braking Systems
Posted Date: 2021-09-02T04:00Z

[Federal Register Volume 86, Number 168 (Thursday, September 2, 2021)]
[Notices]
[Pages 49410-49411]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2021-18997]

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DEPARTMENT OF TRANSPORTATION

Federal Railroad Administration

[Safety Advisory 2021-01]

Positive Train Control Interface Design Issue With Locomotive and 
Cab Car Braking Systems

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

ACTION: Notice of Safety Advisory.

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SUMMARY: FRA is issuing Safety Advisory 2021-01 to make the rail 
industry, including railroads and railroad employees, aware of a 
recently identified interface design issue relating to how positive 
train control (PTC) systems in use throughout the United States 
interface with locomotive and cab car braking systems. This recently 
identified interface design issue allows a train crewmember to 
circumvent a PTC enforcement by manually cutting out the pilot valve/
brake stand, commonly known as the cut-out valve, prior to the PTC 
system initiating the brakes. This interface design issue poses a 
significant safety risk by allowing a PTC system to be disabled and 
unable to initiate the brakes to prevent a train-to-train collision, 
over-speed derailment, incursion into an established work zones, or the 
movement of a train through a switch left in the wrong position. This 
Safety Advisory recommends that all railroads operating with PTC 
systems immediately remind crewmembers that circumventing a PTC 
enforcement is subject to civil penalty or disqualification for the 
locomotive engineer or conductor responsible; audit the designs of PTC 
systems as implemented on all types of locomotives and cab cars; assess 
the extent to which the design of the system could allow a locomotive 
or cab car's PTC system to be circumvented by a crewmember; develop and 
implement a plan to mitigate and/or correct this design issue; and 
provide FRA with a schedule for completion of the identified actions.

FOR FURTHER INFORMATION CONTACT: Gabe Neal, Staff Director, Signal, 
Train Control and Crossings Division, Office of Railroad Systems and 
Technology, at telephone: (816) 516-7168 or email: gabe.neal@dot.gov.

SUPPLEMENTARY INFORMATION:

Background

    Positive train control (PTC) systems must be designed to prevent 
train-to-train collisions, over-speed derailments, incursions into 
established work zones, and the movement of a train through a switch 
left in the wrong position.\1\ PTC accomplishes this by using 
technology to monitor train speed and train locations, provide warnings 
for the traincrew to take action, and automatically initiate braking if 
the traincrew does not take action.
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    \1\ 49 CFR 236.1005.
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    FRA is aware of a recently identified design issue relating to how 
PTC systems in use throughout the United States interface with 
locomotive and cab car braking systems. This interface design issue 
allows a crewmember to circumvent a PTC enforcement by manually cutting 
out the pilot valve/brake stand, commonly known as the cut-out valve, 
prior to the PTC system initiating the brakes. If a PTC system is 
allowed to be disabled by the actions of a crewmember, the PTC system 
can no longer prevent a train-to-train collision, over-speed 
derailment, incursion into an established work zone, or the movement of 
a train through a switch left in the wrong position.
    Although FRA has found that all PTC systems are potentially 
impacted by this interface design issue, FRA notes that only some 
interface designs between the PTC system and the locomotive or cab car 
braking system allow a PTC enforcement to be disabled. FRA believes 
that the interface designs of most concern are limited to a number of 
older locomotives equipped with mechanical braking systems, and the 
interface design is likely not an issue on most newer locomotives 
equipped with electronic braking systems. On PTC-equipped locomotives 
and cab cars with interface designs with this issue, manually cutting 
out the pilot valve/brake stand disables the PTC system enforcement 
capability. FRA recognizes that a locomotive or cab car PTC system is 
considered a ``safety device'' under FRA's regulations \2\ and that it 
is unlawful for a railroad employee to operate the equipment with such 
a safety device disabled without authorization. Accordingly, a system 
that allows such interference in its operation does not comply with the 
applicable statutory or regulatory requirements.\3\ In addition, a PTC 
system that allows such interference presents a significant safety risk 
in that it can no longer perform its required functions.
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    \2\ 49 CFR part 218.
    \3\ 49 CFR 236.1005.
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    FRA became aware of this issue through three recent events:
     On May 27, 2021, during testing of the Advanced Civil 
Speed Enforcement System II (ACSES II) PTC system aboard a freight 
train, an FRA PTC Specialist witnessed an engineer circumvent a penalty 
brake application while operating in an overspeed condition. The 
engineer placed the pilot valve/brake stand in the cut-out position 
prior to PTC system enforcement of the overspeed condition. When the 
overspeed condition no longer existed, the pilot valve/brake stand was 
returned to the cut-in position, and the train continued without a PTC 
system penalty.
     On July 13, 2021, during testing of the Interoperable 
Electronic Train Management System (I-ETMS) PTC system on a freight 
locomotive, FRA conducted a test in which a zero speed temporary speed 
restriction (TSR) was issued to the train and the pilot valve/brake 
stand was placed into the cut-out position prior to PTC system 
enforcement of the TSR. This action allowed the train to circumvent PTC 
system enforcement.
     On July 21, 2021, during testing of the ACSES II PTC 
system on a passenger train, FRA conducted a similar test in which a 
zero speed temporary speed restriction (TSR) was issued to the train 
and the pilot valve/brake stand was placed into the cut-out position 
prior to PTC system enforcement of the TSR. This action achieved 
similar results, allowing the train to circumvent the PTC system 
enforcement with one exception; after placing the pilot valve/brake 
stand back into the cut-in position, the train encountered a PTC 
penalty brake application.

Safety Advisory 2021-01

    As shown by the incidents described above, rail operations face a 
safety risk due to the interface design issue that allows PTC 
enforcement to be circumvented by cutting out the pilot valve/brake 
stand. Such risks must be addressed to provide for the safety of train 
operations, and thus FRA recommends that railroads do the following:
    (1) Immediately remind railroad crewmembers that, along with the 
unauthorized disabling of a PTC system, circumventing PTC enforcement 
by manually cutting out the pilot valve/brake stand when not authorized 
is a revocable event for the locomotive engineer or conductor 
responsible, and

[[Page 49411]]

subjects any other crewmember responsible to individual liability 
proceedings, including disqualification and/or civil penalties. See 49 
CFR 240.117(e)(5), 240.305(a)(5), and 242.403(b) and (e)(5).
    (2) Immediately conduct a complete audit of the PTC onboard design 
of all locomotives and cab cars equipped with PTC to determine how the 
onboard PTC equipment is integrated into each railroad's locomotive and 
cab car's braking system, to ascertain what percentage of the 
locomotive and cab car fleet is subject to the interface design issue 
described above;
    (3) Within ten (10) days of the publication of this Safety 
Advisory, provide FRA, via the SIR site, with a report of the number 
and type of locomotives and cab cars that have this interface design 
issue;
    (4) Upon completion of item (2) above, determine the mitigating 
measures and/or corrective actions necessary to address the safety risk 
presented by the design issue, and provide FRA, via the SIR site, with 
a report documenting the planned measures and/or actions, including a 
schedule for completion; and
    (5) Immediately commence implementation of the planned measures 
and/or actions to address the safety risk presented by the design issue 
per the documented schedule, and provide FRA, via the SIR site, 
confirmation of completion.

    Issued in Washington, DC.
John Karl Alexy,
Associate Administrator for Railroad Safety, Chief Safety Officer.
[FR Doc. 2021-18997 Filed 9-1-21; 8:45 am]
BILLING CODE 4910-06-P