BOSTON — A broken axle caused the June 11 derailment which has led to long-term disruptions of MBTA Red Line subway operations, the transit agency said in a report issued Monday.
Arcing electricity damaged a 27-year-old axle, which fractured and led to the derailment, Boston Magazine reports. The derailment caused extensive damage to signal hardware at the JFK/UMass stop on the Red Line [See “MBTA Red Line subway derailment injures one, disrupts morning commute,” Trains News Wire, June 11, 2019.] Slowdowns in operation from that accident are still continuing.
The MBTA inspected the rest of its Red Line fleet for similar issues and replaced seven axles as a result, as well of two grounding rings that are supposed to prevent arcing issues. The grounding rings had worn on the axle that broke.