This information is preliminary and will be either supplemented or corrected during the course of the investigation. Release date 1 DEC 2021.
On October 12, 2021, about 4:51 p.m. local time, Washington Metropolitan Area Transit Authority (WMATA) train 407, consisting of eight 7000-series railcars, was traveling southbound on track 2 of the blue line between the Rosslyn and Arlington Cemetery stations in Arlington, Virginia, when one wheelset on railcar 7200 derailed. Of the 187 passengers onboard, 1 passenger was transported to the hospital for treatment; no other injuries were reported. The evacuation, coordinated by WMATA and the Arlington County Fire Department, began about 6:20 p.m. and concluded about 7:16 p.m. Passengers were safely evacuated onto the track bed through the end railcar door and escorted south to the Arlington Cemetery station. Damage by WMATA is estimated to be $715,000.
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. Initially unaware of car 7200’s wheelset derailment, the train operator reported to the rail operations control center that he believed there was a stuck brake on car 7200. The rail controller instructed the train operator to try to move the train. The attempt was unsuccessful, and when a WMATA supervisor arrived on-scene, they determined that the lead axle on car 7200 derailed. Power to the third rail (an additional rail supplying electric current) was disconnected at 5:03 p.m.
While on scene, National Transportation Safety Board (NTSB) investigators conducted track and equipment inspections, reviewed signal and train control data logs, reviewed station video, obtained data from data recorders, and conducted interviews. The NTSB identified that the point of derailment was in the frog of a turnout about 166 feet south of the Rosslyn station.[1] The maximum authorized speed through the area is 59 mph.
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, about 3:23 p.m. one of car 7200’s wheelsets derailed and rerailed while moving through a pair of switches, and the train continued traveling toward the Largo Town Center station. As the train departed the Largo Town Center station on track 2, about 4:13 p.m. the same wheelset on car 7200 derailed and rerailed again while moving through a pair of switches, and the train continued inbound through Washington, DC, toward Arlington, Virginia, where the accident occurred. (See figure 1.) Broken sections of brake discs were recovered at the crossover location north of the Arlington Cemetery station and at the turnout near the Largo Town Center station.
Figure 1. Map of the WMATA blue and silver lines with the locations where 7200 derailed noted.
The 7000-series cars were manufactured by Kawasaki Rail Car Inc. For their contract with WMATA, Kawasaki Railcar Inc. subcontracted with Sumitomo Metals to supply the wheels and axles and with ORX to assemble the wheelset by pressing the wheels onto the axles.[2] WMATA’s design specification specified the linear distance between the wheels on the axle (the gage) is 53-5/16 inches ±1/16 inch. (See figure 2.)
Figure 2. Depiction of WMATA’s wheel design specification. Diagram of accident area.
The NTSB examined car 7200 and found that both wheels had moved outboard from their seats, increasing the gage 2 inches, which exceeded the design specifications. The NTSB also observed increased wear of the wheels.
Based on the track and accident wheelset examinations, WMATA began a fleet inspection of its 7000-series cars on October 15, 2021. The inspections focused on the wheel and axle assembly to identify other cars with wheelsets that did not meet specifications, similar to car 7200.
After WMATA began the 7000-series fleet inspections, the Washington Metrorail Safety Commission, which is the state safety oversight agency for the WMATA rail system, reviewed the interim results.[3] On October 17, 2021, the Washington Metrorail Safety Commission ordered WMATA to remove the 7000-series railcars from revenue service, stating:
The prevalence of this defect throughout the 7000 Series railcar fleet is unknown and an inspection interval that is adequate to detect this defect before a safety event occurs has not been determined.
On October 26, 2021, WMATA reported to NTSB that inspection of all 748 cars was complete. WMATA identified an additional 20 wheel and axle assemblies that are out of specification and exhibited outward movement of the wheel on the axle.
On November 1, 2021, the Federal Transit Administration issued “Safety Advisory 21-1; Fleet-Wide Inspection of Wheel Gauging on Rail Rolling Stock” directing state safety oversight agencies to report information to the Federal Transit Administration regarding out-of-tolerance wheel gages on all rail transit rolling stock in revenue service by December 1, 2021. The Safety Advisory also advises state safety oversight agencies to require fleetwide inspections of wheel gages at rail fixed guideway public transportation systems in their jurisdiction by January 3, 2022.[4]
The NTSB investigation is ongoing. Future investigative activities will focus on failure analysis of the subject 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 rail cars.
Parties to the investigation include the Federal Transit Administration, Washington Metrorail Safety Commission, WMATA, the Amalgamated Transit Union, Kawasaki Railcar Inc., and ORX.1 (a) Turnouts are track configurations that allow a train to be guided from one track to another. (b) A frog is a track component within a turnout that allows the train wheels on one rail of track to cross another rail of an intersecting track.
- (a) Turnouts are track configurations that allow a train to be guided from one track to another. (b) A frog is a track component within a turnout that allows the train wheels on one rail of track to cross another rail of an intersecting track.
- On October 1, 2012, Sumitomo Metals formed a partnership as Nippon Metals & Sumitomo Metal Group, which became Nippon Steel in 2019. The wheels were forged in Osaka, Japan.
- In accordance with Title 49 Code of Federal Regulations Part 674, a state safety oversight agency is responsible for “overseeing the safety of the rail fixed guideway public transportation systems within the State.”
- Rail fixed guideway public transportation system means any fixed guideway system that uses rail, is operated for public transportation, is within the jurisdiction of a State, and is not subject to the jurisdiction of the Federal Railroad Administration, or any such system in engineering or construction as defined in Title 49 Code of Federal Regulations 674.7.
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