Train services on the Harbour line were affected since early morning after a ballast train derailed at Chhatrapati Shivaji Terminus station. This happened at around 5.15am near the station when preliminary work of Harbour line extension was underway.

The Central Railway authorities shut services between Wadala and CST stations to clear the track, thus affecting the morning peak hours too. Ballast train is used to put stones between the rail track and cement sleepers, thus acting like a cushion for the train while moving.