On Wednesday, October 13, 2021, Metro began working with NTSB and the WMSC to determine the cause of the Blue Line derailment at Arlington Cemetery; that investigation is still ongoing.
Metro removed all 7000-series railcars, roughly 60 percent of its fleet, from passenger service.
Last week, March 24, Metro updated the board and public that outside experts Transportation Technology Center, Inc. (TTCI) continue to lead the independent root cause investigation.
Metro is in the design and execution stage of four static and three dynamic tests to recreate specific operational conditions, driven by the data analysis, with static testing starting in April at the wheel manufacturer (ORX) facility in Pennsylvania.
The root cause appears to be a combination of factors. Metro is currently working with WSMC to receive approval for daily inspection of 7000-series trains using a digital gauge to measure performance.
On January 12, Metro announced 7000-series trains will remain out of passenger service for about 90 days to allow engineering and mechanical experts time to focus on the root cause of the derailment and acquire new technology to measure 7000-series wheelsets.
Metro’s full letter to WSMC can be seen here.