The Federal Railroad Administration (FRA) has published a Safety Advisory on a Positive Train Control (PTC) issue recently identified during testing of ACSES II (Advanced Civil Speed Enforcement System II) and I-ETMS (Interoperable Electronic Train Management System) technology.
FRA reported in the Federal Register on Sept. 2 that an interface design issue “allows a train crewmember to circumvent a PTC enforcement by manually cutting out the pilot valve/brake stand. …” This permits the 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.”
While all PTC systems are potentially impacted, “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.”
FRA is recommending that all freight and passenger railroads operating with PTC:
“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.”
Download Safety Advisory 2021-18997 here: Download