The National Transportation Safety Board (NTSB) issued a Safety Alert calling on rail transit agencies and commuter railroads across the nation to assess its fleets for wheelsets that do not meet gage specifications and to take immediate action to correct the problem.

Safety Alert 083 “Passenger Railcar Wheelset Alert” urges transit agencies and commuter railroads to address a condition in which wheels on certain railcars in the Washington Metro system moved outward from their mounted position on the axle.

​“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, 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.”

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, NTSB noted.

The wheelset movement issue was identified during NTSB’s ongoing investigation of the Oct. 12 derailment involving a WMATA train traveling southbound on Metro’s Blue line between the Rosslyn and Arlington Cemetery stations in Arlington, Virginia. Of the 187 passengers onboard, one passenger was transported to the hospital for treatment.

In the preliminary report also issued Wednesday on the Oct. 12 accident, NTSB investigators said the train had departed the Rosslyn station when one wheelset on the fourth car of the train, car 7200, derailed. After it derailed, the train traveled about 1,800 feet before stopping in the tunnel. All railcars remained upright and inline.

A preliminary review of data from an onboard event recorder revealed the train speed was about 33 mph at the time of the derailment. Based on physical evidence and station video review, between the Arlington Cemetery and Rosslyn stations, one of car 7200’s wheelsets derailed and rerailed while moving through a pair of switches. The train continued traveling toward the Largo Town Center station. NTSB found that when the train departed the Largo Town Center station, the same wheelset on car 7200 derailed and rerailed again while moving through a pair of switches, and the train continued inbound through Washington, D.C., toward Arlington, Va., where the accident occurred.

The NTSB investigation is ongoing. Additional investigative activities will focus on failure analysis of the wheelsets, evaluation of the response from rail traffic controllers, internal and external oversight of the WMATA system, and identification of similar wheelset issues on passenger railcars.

Safety Alert 083 is available online here.

The NTSB preliminary report is available here.