Design issue could allow Positive Train Control systems to be disabled, FRA warns

Washington — The Federal Railroad Administration has issued a safety advisory to railroads and rail employees regarding a recently identified interface design issue that relates to how Positive Train Control systems interface with locomotive and cab car braking systems.

PTC systems are emergency slowing and stopping mechanisms designed to help prevent train crashes and derailments caused by human error.

According to a notice published in the Sept. 2 Federal Register, the issue allows a train crew member to circumvent a PTC enforcement by manually cutting out the pilot valve/brake stand – known commonly as the cutout valve – before the PTC system initiates 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 zone or the movement of a train through a switch left in the wrong position,” the notice states.

Railroads should immediately remind crew members that circumventing a PTC enforcement is subject to civil penalty or disqualification for the locomotive engineer/conductor responsible. FRA also encourages railroads to:

• Audit the designs of PTC systems implemented on all types of locomotives and cab cars.
• Assess the extent to which a PTC system’s design could be circumvented by a crew member.
• Develop and implement a plan to mitigate and/or correct the design issue.
• Provide FRA with a schedule for completion of the identified actions.