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Federal Register / Vol. 86, No. 168 / Thursday, September 2, 2021 / Notices
By the Board, Scott M. Zimmerman, Acting Director, Office of Proceedings.
Raina White, Clearance Clerk.
FR Doc. 202118972 Filed 9121; 8:45 am BILLING CODE 491501P

DEPARTMENT OF TRANSPORTATION
Federal Railroad Administration Safety Advisory 202101

Positive Train Control Interface Design Issue With Locomotive and Cab Car Braking Systems Federal Railroad Administration FRA, Department of Transportation DOT.
ACTION: Notice of Safety Advisory.
AGENCY:

FRA is issuing Safety Advisory 202101 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 trainto-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 cars 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
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SUMMARY:

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telephone: 816 5167168 or email:
gabe.neal@dot.gov.
SUPPLEMENTARY INFORMATION:
Background Positive train control PTC systems must be designed to prevent train-totrain 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.
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 PTCequipped 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 FRAs 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
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CFR 236.1005.
CFR part 218.
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system that allows such interference presents a significant safety risk in that it can no longer perform its required functions.
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 IETMS 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 202101
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
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