MBTA service on the Ashmont branch of the Red Line was disrupted for more than four hours this morning after the third rail cracked near the JFK/UMass station in Dorchester, MBTA officials said.
The defect was discovered shortly after 7 a.m. on the northbound tracks, said MBTA spokesman Joe Pesaturo.
Service was restored shortly after 11 a.m., he said.
“Below freezing temperatures are believed to be a contributing factor” to the crack, Pesaturo said.
A third rail cracked last night in the same general location, only on the Braintree side of the JFK station, causing some delays, Pesaturo said.
Twenty buses were deployed to provide service between Ashmont and JFK stations while crews repaired the third rail.
Space on the JFK/UMass train platform was limited this morning as commuters packed the station waiting for buses and trains.
Mike Digiacomo, who rides the Red Line from Braintree to Alewife in the mornings to work, said he arrived 15 minutes late today because of the MBTA delays. He said commuters were packed into every station, but many couldn’t get on his train because it was already full of people.
“Park Street [station] was super crowded because everybody was delayed,” he said. “It was elbow to elbow, people everywhere.”