An overheated insulator caused a fire near Orange Line tracks on Wednesday that sent smoke spewing through a station and triggered substantial delays, MBTA officials said.
The operator of a southbound Orange Line vehicle "reported flames within the track area in front of the train" at Tufts Medical Center around 11:50 a.m. on Wednesday, T spokesperson Lisa Battiston said in a statement.
Riders shared images of smoke filling the air at the station, and firefighters responded to the scene. No one was injured, according to Battiston.
The incident prompted significant delays and suspension of subway service between North Station and Back Bay. Workers from the T's power department completed repairs and normal service resumed around 2 p.m., Battiston said.
"It was subsequently determined that the incident was caused by an overheated third rail insulator," Battiston said. She later added, "Our Engineering and Maintenance teams are taking a closer look at the conditions of all of the third-rail insulators through the area, and will replace any that warrant it."
The MBTA posted several updates about service impacts on Twitter over the course of Wednesday, informing riders about delays and the temporary partial Orange Line closure, though it did not put out a press release about the incident or subsequent investigation. Battiston said the agency also sent alerts via its T-Alerts system and in announcements on trains and in stations.