Metrorail train on tracks near National Airport by thisisbossi licensed under Creative Commons.

Metro’s General Manager ordered inspections of the agency’s 2000- and 3000-series railcar fleet after a brake part that fell off of an older train led to the derailment of a 7000-series train on Friday, September 29, outside National Airport. No injuries were reported after the derailment and Metro’s response improved compared to last time, but questions remain about why and how it was able to occur.

At about 10:45 am on Friday, Blue Line train 406 leaving National Airport towards Franconia-Springfield ran over a metal object sitting on one of the tracks. Front-facing camera footage from the lead car of the train shows what Metro says is a brake disk leaning against the left rail, causing the train to derail.

The brake disc, as shown in the image below, came off of a 2000- or 3000-series car from a train that ran through the area before the 7000-series one. A statement issued by Metro on Sunday said that its crews had inspected the derailed 7000-series train, as well as the tracks themselves, and found no mechanical or systems defects outside of the loose brake that would have caused the derailment.

Diagram of a disc brake from a Metrorail 7000-series train. The brake systems under scrutiny are from 2000- and 3000-series trains. Image from WMATA.

Inspection procedures under scrutiny

Metro General Manager Randy Clarke pulled all 2000- and 3000-series railcars from service on Saturday, September 30, after inspectors found 12 cars with loose brake disc bolts. Inspections remain ongoing, but as of the agency’s statement Sunday, 32 of 102 inspected railcars had been identified with “non-confirming bolts” — likely meaning bolts that came loose. As of Monday, the number of cars with loose or broken bolts had grown to 60 cars with “at least one loose bolt,” out of 80% of the 2000- and 3000-series cars inspected.

Given the ongoing investigation, it is unclear how long those cars will remain out of service, how many more will be found during inspections, or any implications for the rest of Metro’s railcar fleet.

Metro has approximately 350 active 2000- and 3000-series railcars, which make up just over 25% of the active fleet. Breda, the manufacturer of the cars, is now part of Hitachi Rail Italy, the chosen vendor to build Metro’s upcoming new 8000-series railcars.

Metro VP and Chief Mechanical Officer Shushil Ramnaress stated in a video released on YouTube that the agency’s inspections had found bolts on inspected cars had worn out. “Some of these bolts are loose…the bolts had failed, so they’ve sheared off, which resulted in the brake rotor falling off the car.”

Railcars are inspected every 60 (A Inspection), 180 (B Inspection), and 360 (C Inspection) days, each with increasing levels of thoroughness. Metro inspection documents indicate that brake discs are inspected as part of the “A” Periodic Inspection (PI).

The protocol for maintenance technicians notes to inspect the brake discs to ensure they’re seated securely, to check the surface for signs of wear or damage, and to ensure “that all bolts are properly secured and torque strips are in place.” Torque strips are thin layers of lacquer laid across the head of a bolt to visually indicate if it is still tightened as expected, or if it has become loose.

The disc brake units on 2000- and 3000-series cars are also similar in nature to those found on the 7000-series cars, though those cars were not included in the GM’s emergency inspection. Metro’s rail fleet management plan notes that the “specific inspection and preventive maintenance requirements differ somewhat by car series.”

A portion of the inspection activities performed on Metro’s 7000-series trains every 60 days. Among them is the inspection of brake pads and brake discs. Image from WMATA.

Metro notes it is investigating the derailment and brake disc issue alongside the Washington Metrorail Safety Commission (WMSC), which is responsible for performing safety oversight of the rail agency.

Yellow and Blue Line trains single-tracked between the National Airport and Potomac Yard stations from Friday through Monday, October 2, while Metro track, structure, and signaling crews repaired rail, grout pads, third rail, and other components damaged by the derailment.