The National Transportation Safety Board (NTSB) issued a Safety Alert on Dec. 1 recommending transit agencies and commuter railroads assess gauge specifications of their fleets and urge immediate corrective action should any wheelsets be found to be outside these specifications.
NTSB also notes it supports the Federal Transit Administration’s (FTA) safety advisory issued Nov. 1, 2021 directing State Safety Oversight Agencies (SSOA) to report out-of-tolerance wheel gauges on all rail transit rolling stock in revenue service and conduct inspections of wheel gauges at rail fixed guideway public transportation systems (RTAs) in their jurisdiction.
“The Safety Alert identifies the issue of wheelset movement on transit railcars and commuter railroads as a serious problem that has the potential to create a catastrophic event,” said Robert Hall, director of the NTSB’s Office of Railroad, Pipeline and Hazardous Materials Investigations. “As we continue to conduct the investigation of this derailment, it is imperative that the safety issues identified are addressed immediately to protect the American public traveling daily on our transit system.”
Wheelset specifications have been in the spotlight following an Oct. 12 derailment involving a Washington Metropolitan Area Transit Authority (WMATA) MetroRail Blue line train in Arlington, Va. NTSB’s preliminary report determined the incident occurred when a wheelset on the fourth car of the train derailed. The same wheelset derailed and then rerailed while moving through a pair of switches two times the day of the incident before derailing a final time.
WMATA was directed to remove its 7000 series railcars from service after the incident so each wheelset could be inspected and tested.
NTSB explains an out-of-specification wheelset is not easily identifiable with a routine visual inspection, consequently, the condition could exist on wheel and axle assemblies of other transit or commuter railcars.
While NTSB noted in the Safety Alert that the derailment “likely occurred due to movement of the wheel on its axle,” a probable cause for the derailment has not been determined and NTSB continues its investigation.
The NTSB Safety Alert can be viewed here.