Unapproved process change grounds Metro’s 7000-series railcars (again)

Now you see them, now you don’t. Metro’s 7000-series railcar fleet has been grounded, again, after inspections performed by the Washington Metropolitan Safety Commission (WMSC) discovered at least five of fourty 7000-series cars put back into passenger service didn’t “meet the inspection criteria specified” in the procedures Metro submitted for the commission’s approval.

The 7000-series railcars make up the majority of Metrorail’s fleet, and outside this incident are the most reliable — without them, Metro’s service has taken a serious hit. There is no time frame yet for when the cars might return to service.

The WMSC initially ordered that the 7000-series cars be removed from service after a Blue Line train derailed outside Arlington Cemetery on October 12 last year. The derailment was caused by the wheels on an axle moving when they shouldn’t have been, an issue that some inside the agency had known about since it surfaced in 2017. The wheels on 52 axles between 2017 and 2021 were measured to be out of tolerance — sitting wider or narrower than they should have been — which could lead to a derailment.

After an initial testing plan was submitted to the WMSC, Metro began reintroducing the 7000-series railcars on December 17. A new protocol approved by the WMSC as part of Metro’s 7000-series Return To Service (RTS) plan included weekly wheel inspections (“back-to-back measurements”), rather than every 90 days, and a process that dictated what happened if a wheelset failed the inspection.

The WMSC order issued on December 29 says Metro must now keep all 7000-series railcars out of service until it provides a revised Return To Service plan to account for the issues it discovered recently and to describe how the agency will ensure its employees follow the plan.

Metro spokesperson Ian Janetta said via email that the 7000-series railcars are out of service while Metro and the WMSC “clarify the confirmation process for measurements once wheelsets are identified as requiring additional follow up within our criteria.“ Janetta says the new order won’t cause trains to run less frequently than they do today.

WMSC to Metro: follow the plan, please

The WMSC order, in short, wants to make sure that Metro staff and employees follow the plan as submitted and approved by the oversight body.

A memo from Metro GM/CEO Paul Wiedefeld to the agency’s Board of Directors states as the agency began implementing new wheelset inspections, “it became clear that the limits of the precision of the available tools…resulted in challenges” and Metro revised the process. Agency staff, it says, “implemented the revised process without receiving approval from the WMSC.”

First, the WMSC says Metro needs to describe what the agency will do to ensure that railcars that should be out of service stay out of service, and aren’t mistakenly allowed to run with passengers onboard.

Second, the WMSC is requiring Metro to describe how Metro will “ensure that no alternative procedures or practices are introduced outside of the official RTS plan.”

Third, the WMSC wants Metro to describe and explain its revised wheel inspection frequency - which the agency and an outside consultant increased to daily, instead of weekly - and include more recent data taken into December.

A technical procedure revision may be to blame

In documentation submitted and approved by the WMSC, back-to-back measurements are to be taken using a tool called an incremental measuring gauge, to see how far apart the wheels on the axle are. Metro’s standard specifies the wheels should be 53 and 5/16” apart from each other, plus or minus 1/16”. If a wheelset fails inspection using the incremental measuring gauge, a second tool, a “dial gauge,” is supposed to be used to take a more accurate measurement to verify the failure.

The incremental measuring gauge provides engineers with measurements down to 16th-inch increments. The dial gauge is more accurate and shows engineers measurements down to three decimal places.

The procedure for taking the back-to-back measurement appears to have been revised between what Metro submitted to the WMSC and what Metro is currently using today, which likely led to the WMSC’s new requirement to ensure no “alternative procedures” are introduced without their knowledge.

In the procedure approved by the WMSC, the incremental gauge measurement would need to be both less than or equal to 1/16” off the expected wheel separation distance, and also less than 1/32” different from the wheel’s prior measurement. If the wheel fails the first measurement, inspectors would need to use the more accurate dial gauge to verify if there’s actually an issue.

Metro engineering personnel appear to have made two changes to this inspection procedure. First, the incremental gauge measurement would now pass if it’s less than or equal to 1/32” off of the prior measurement, not just less than. A second change to the procedure removed the dial gauge as a verification check. Instead, if either 1) the back-to-back measurement was less than 53-4/16” or greater than 53-6/16”, or 2) the difference from the prior inspection were greater than 1/32”, the wheel inspection would fail.

WMSC spokesperson Max Smith said in an email that an example issue found by the WMSC “is Metrorail stating that it would keep any car out of service if a measurement was 1/32 inch or more different from the prior measurement.” The five non-conforming cars Metro had in service on that day, December 29, did not meet those requirements.

The December 29 order states Metro needs to submit any further changes to its RTS plan to the WMSC for a 14-day review period prior to implementing any new updates.

Procedure revisions pause the 7000-series reintroduction clock

Metro had initially hoped to release 336 7000-series railcars within the first three weeks of getting WMSC approval to return them, but that no longer seems possible. Daily wheel inspections, being performed at three yards across two shifts, limits the number of railcars that can be put into service to about 192, or approximately 24 trains at most.

The extra cars are needed to boost Metrorail service levels back to normal. Trains currently run every 12 minutes on the Red Line, and every 20 on all others; at normal service levels, they should run every 6 on the Red Line and and every 10-12 on all others.