PTC cutout
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 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 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.
