The wheels on Metro’s 7000-series trains may not have been put on securely enough

A technical specification that changed how the 7000-series trains’ wheels were put onto their axles appears to be a possible contributing factor to the Blue line derailment outside Rosslyn on October 12, and the likely cause of multiple inspection failures that, if left unaddressed, could have led to more derailments since the introduction of the railcar fleet.

Metro published a Request for Proposals to buy new railcars last decade, and Kawasaki Rail Car was one among several companies that replied. During a period of contract, specification, and language negotiations with the railcar manufacturer, the two settled upon a design of a new railcar. That spec became the 7000-series trains.

Nestled inside the specification of the design was one detail which may have made all the difference: how hard the wheels were pushed onto and secured to their axles. A significant amount of force is used when pushing wheels from either side onto the central axle to secure the wheels - in the range of tens of tons. Metro’s initial specifications did not include a specific pressure range to use, but Kawasaki’s drawings did.

According to Metro documents viewed by Greater Greater Washington and sources familiar with the investigation, the original specification of the 7000-series contract called for the wheels to be assembled onto the axles at a lower pressure specification than the rest of the railcars that Metro has in service. Instead of putting the wheels on with between 65 and 95 tons, the original specification called for the application pressure to be 55 to 80 tons.

The original specification was changed to match the rest of the Metrorail fleet in 2017 after a “wheelset inspection event” at the manufacturer’s facility. Kawasaki, the lead 7000-series contractor, found evidence that one or more wheels were rubbing up against a rail intended to help keep train wheels on the tracks and preventing them from straying too far if they derail.

The incident at the manufacturer caused Metro to ask if the pressure specification could be increased to reduce the risk of the wheels moving and so that it would match what Metro uses for the rest of its fleet. Kawasaki confirmed and made the change, but not before hundreds of wheelsets were already produced.

In Kawasaki’s response, they asked Metro a question: “Please clarify what WMATA would like to do with the wheelsets already provided with the current mounting requirements.” It is unclear if Metro responded to the question.

Metro directed GGWash’s questions about the specification change to the NTSB; the Washington Metrorail Safety Commission (WMSC), the independent oversight body overseeing Metrorail, declined to comment. ORX, the wheelset manufacturer, declined to comment, citing customer privacy. The NTSB did not reply to an email with questions about the change.

Metro’s earlier 7000-series trains affected

Metro’s 7000-series trains were delivered between 2014 and 2020, totaling 748 railcars. The specification change made in 2017 was about half-way through the railcar order, meaning just over half of Metro’s newest railcar fleet’s axles were built with a lower specification requirement than the other cars.

Railcar 7200 was the one which derailed outside Rosslyn on Oct. 12, and many of the 52 other inspection failures identified by Metro and the NTSB were similarly on lower-numbered 7000-series railcars. Some of the wheelsets on the 7000’s produced later during manufacturing have also been inspected and found to be spaced wider or narrower than allowed.

Metro performs a type of inspection of its railcars every 90 days, which includes what’s referred to as a “back to back measurement” - the distance between wheels on a railcar’s axles. The inspection failures refer to an individual axle that failed the measurement and were 1/16 of an inch wider or narrower than the expected width between. When axles failed inspections, Metro says those cars would be removed from service and the wheelsets replaced before they could go back out.

The NTSB noted in a press conference earlier in the week that the number of wheelset defects identified by Metro inspections had been going up over time. There were 2 reported in 2017, 2 in 2018, 4 in 2019, 5 in 2020, and 18 in 2021. An additional 21 were identified by the NTSB after the Blue line derailment, bringing the total up to 52 wheelsets out of tolerance during that time.

At the same time, Metro was receiving more 7000-series trains too. According to data recorded by this author, the agency had received approximately 470 7000-series railcars by the end of 2017, 610 by the end of 2018, around 730 by the end of 2019, and all 748 delivered by the end of 2020. The rate of inspection failures per axle - each railcar has four axles - in service still appears to rise over this time from 0.01% in 2017 to 1.3% in 2021 when counting failures identified both by Metro and the NTSB.

Metro was instructed by the WMSC to remove all 7000-series trains by Monday the 18th at 5am. The cars can’t be placed back into service until Metro submits a plan to ensure it’s safe to do so, and the WMSC signs off on it.

According to Max Smith, WMSC spokesperson, “We are continuing to receive and discuss information and aspects of WMATA’s proposed plans as Metrorail develops its plans required by the order.”

Getting every railcar in service

With so many railcars out of service, Metro is in a bind. The agency announced Sunday that trains on all lines would run every 30 minutes this week, and more recently announced trains would run at reduced levels - 30 minutes on all lines, every 15 for the Red Line, and SIlver Line trains are turning back at Federal Center to Wiehle - through at least the end of the week.

Metro announced Friday that “Metrorail service will remain at the current reduced service levels through at least October 31, 2021.”

Of the agency’s 1,278-railcar fleet, only about 312 cars are potentially available for passengers to ride, a far cry from the agency’s regular schedule that calls for 864 cars to be used in revenue service on a daily basis. Assuming all of Metro’s 278 3000-series cars are available, the agency says it also expects to have 18 2000-series railcars available, as well as 16 6000-series cars around for use for service this week. A number of those cars are out of service for regularly-scheduled maintenance and overhauls, or are waiting on service. Metro announced Sunday it would be able to run 40 trains with 240 cars.

The grounding of the 7000-series fleet comes at a most inopportune time for Metro. The vast majority of its 6000-series fleet (180 cars) are still grounded after two trains pulled apart on the Red Line. Metro has returned 16, or just under 10%, of the cars to service.

The 2000-series trains are also mostly out of service at the moment for an unrelated reason: the pandemic. Since Metro has been running fewer trains than usual, the spares were put into “cold storage” and prepared to be parked out of service in the rail yards for an extended period of time. Metro is now trying to get some of those cars inspected, repaired if needed, and ready to be placed back into service as soon as possible.

Logistics, unfortunately, is a stumbling block in Metro’s plans to place as many railcars into service as they can. The grounding of the 7000-series cars led to a mass scurry of activity getting those cars into the rail yards before a 5am Monday deadline. In the process, Metro potentially blocked in some cars that would otherwise be good to put into service but then ended up stuck. Like a gamer playing Tetris, agency staff had to turn to figuring out how to move trains around rail yards, made more complicated when the yards are full, to try and reach those cars.

The shutdown at Rockville for the station’s canopy replacement project didn’t help either. While many of the cars in the rail yard at Shady Grove were able to be removed and taken to other yards before the project began, not every one was. A handful of cars were still present in the rail yard on Wednesday, unable to be towed through the Rockville work zone due to the canopy project.

While Metro staff are busy trying to recover service, the Metro Board of Directors have hired external consultants to assist them as well. A statement by Board Chairman Paul Smedberg says the consultants will assist with “safety, operations and organizational accountability of Metro.”

Update: This article was updated at 11:10 am, Friday, Oct. 22, to reflect Metro’s latest announcement about reduced Metrorail service.