Take two: Metro tries again to return some 7000-series railcars to service
In a long-awaited announcement, Metro on Thursday said it had submitted a plan to the Washington Metrorail Safety Commission (WMSC) outlining the steps it would take in order to return some 7000-series railcars to passenger service. The cars have been grounded for just over seven months after a train derailed outside of Arlington Cemetery and the resulting investigation into the root cause remains ongoing.
Metro has been running fewer trains since the derailment grounded all the 7000’s last October, which make up over half the agency’s railcar fleet. Rail lines which ran at 8-minute intervals before the derailment now run every 15 or 20, and the agency has not had enough railcars available to run any train with eight cars, only six.
The initial plan to restore some 7000-series railcars to service is built upon manual inspection processes wherein the wheels and axles of each 7000-series railcars would need to be inspected each morning before being placed out into service. The agency has plans to transition towards automated field-based monitoring of the wheelset assemblies, but has not obtained approval from the WMSC to do so.
Metro sources indicate that the agency plans to restore eight trains, or 64 railcars, to service with the plan now approved, though a Metro public relations officer said the exact number was still to be determined. The agency has a total of 748 7000-series railcars.
The longer-term strategy that Metro is banking on is a system of six Automatic Wayside Inspection System (AWIS) devices throughout the Metrorail network. The AWIS devices would automatically monitor the wheels on Metro’s railcars to report data about their configuration, for instance how far apart the wheels are. The October derailment occurred because the wheels on a 7000-series car had moved two inches further apart than expected and left the tracks.
The WMSC says Metro’s plan submitted on Thursday is acceptable, and the safety oversight commission had “no technical objections” to it. The commission had previously ordered Metro to first to ground the 7000-series fleet in October, but then to keep the fleet grounded after Metro procedure lapses allowed several railcars which failed wheelset measurements to be put back into service.
The vast majority of the 7000-series fleet remains out of service while the investigation into the derailment, led by the National Transportation Safety Board, continues. Metro brought on its own contractor, MxV Rail (formerly known as TTCI) to assist in determining the root cause why the wheels on 7000-series trains have been moving apart.
The wheel issue on the train that derailed was just the latest in an increasing number of wheel “back to back” distance failures, which the NTSB publicized last fall. Over 40 7000-series railcars had failed wheelset inspection measurements between 2017 and 2021 because the wheels were too far apart. After the derailment, the agency and NTSB investigators found an additional 21 failed wheelsets.
One factor at play in the investigation - but not the root cause - is the “press tonnage,” or how securely the wheels were pressed onto their axles during manufacturing. After a “wheelset inspection event” occurred at the wheelset manufacturing facility, Metro requested the press tonnage be increased to match its current specification, but appears to have never told Kawasaki what to do about the wheelsets that had already been manufactured.
Metro hopes to have the rest of the 7000-series fleet back in service “in late summer,” though that is far from guaranteed. Much depends on Metro’s execution of the manual inspections - especially adherence to protocols - and how the agency proceeds in its installation and configuration of the AWIS devices.
For now, riders continue to see trains every 10 minutes on the Red Line, and every 15 minutes all day on all other lines.