Rail experts say Orange Line battery ‘failure’ was likely a battery explosion; no answer from T

T officials inspected a new Orange Line T train last year just outside the Wellington MBTA station.Matthew J Lee/Globe staff

Two rail experts said Wednesday that a battery explosion on a new Orange Line car earlier this week was likely behind the MBTA’s decision to keep all new Orange and Red Line trains away from passenger service.

MBTA spokesperson Lisa Battiston said a “battery failure” Monday while the car was out of service at Wellington Yard “dislodged the battery cover from an external underside compartment of the vehicle,” and caused “significant” damage to the battery and the “part of the train where the battery is located.”

She said that “failure” led the T to remove new cars from service, but declined to answer if it was an explosion.

Robert Halstead, a New York-based railroad accident reconstruction expert with Ironwood Technologies, called Battiston’s description of the incident “extremely sanitized,” and said the battery most likely exploded. Based on the description, Halstead said, “an internal explosion would be the only thing I can think of. My money would be with exploded.”

Rail safety expert and consultant Keith Millhouse, who formerly served as board chairman for Southern California’s Metrolink commuter rail system, said he is confident based on Battiston’s description that the battery exploded.

“There would be no other way to account for the damage if there wasn’t an explosion of some kind,” he said.

Battiston and Troy Wall, a spokesperson for the Massachusetts Department of Public Utilities, did not respond to repeated questions from the Globe Tuesday and Wednesday about whether or not a battery exploded. The DPU is charged with ensuring that the MBTA is in compliance with federal safety laws.

Wall said DPU staff reviewed the incident at the Wellington Yard on Monday.

“The DPU’s role is to monitor the MBTA’s ongoing investigation into the root cause of the issue, and to review the sufficiency of the investigation,” he said via e-mail.

A spokesperson for the Federal Transit Administration, which is inspecting safety at the MBTA, said Monday’s Orange Line battery incident did not meet the threshold requiring reporting to the federal agency because it did not cause injury or evacuation.

The battery incident is the latest in a growing series of safety-related problems with the new Orange and Red Line cars. Just last month, the MBTA pulled all of them out of service after discovering a bolt on one of the car’s brakes was improperly installed.

The MBTA is still waiting for delivery of hundreds of new Orange and Red Line cars from a Chinese company first contracted in 2014 to replace the more-than-50-year-old cars like the one involved in the death of Robinson Lalin, who was dragged with his arm stuck in a train door at Broadway Station in April.

The FTA expects to wrap up its inspection by August, but has demanded the MBTA fix four safety problems as soon as possible. In response to the problem of understaffing at the operations control center highlighted by the FTA last week, the T slashed subway service starting Monday.

The MBTA has known about its staffing issues since at least 2019, when an outside group of experts hired by its former oversight board warned that “safety is not the priority,” partly because the MBTA was taking far too long to staff up and falling so short in investigating and preventing failures.

Even as the T has added new positions to its books, hundreds of safety-related jobs across the system, including in the operations control center, have remained unfilled. As of May 31, the MBTA had budgeted for, but not yet filled, 586 open safety jobs, nearly triple the number of vacancies from just two years prior.