SAN FRANCISCO (KRON) — The BART track between Concord and Pleasant Hill where yesterday a train car partially derailed has returned to single-track service Wednesday morning around 5 a.m., according to a tweet from BART. BART service is again running in both the SFO and Antioch directions.

BART did not have an estimate as to when full service between Pleasant Hill and Concord would be restored.

“We anticipate that the current single-line service will last throughout the rest of the day and evening. We can update you if there are any changes to the service plan,” said Chris Filippi of BART’s External Affairs Department in a statement.

The route’s service toward SFO was suspended yesterday after a train partially derailed, which officials attributed to the extreme heat causing a curve in the track. Riders instead took buses between the two stations while crews worked to evacuate passengers and clear the tracks.

Crews worked through the night on the tracks and it is “thanks to their work” that the service has returned. according to the tweet.

The rest of the Yellow Line will continue with normal service. BART warned that riders will likely see delays of between five and 15 minutes because of the single track service.