Photo gallery: Power fault causes N-E Line breakdown for 6 hours
Train services on the North-East Line resumed at about 4.40pm on Thursday after a six hour disruption.
At about 9.51am on Thursday, a power fault on the stretch between HarbourFront and Outram Park caused a delay of train service in both directions.
SBS Transit said it decided to disrupt services between HarbourFront and Dhoby Ghaut to allow engineers to enter the tunnel and repair stainless steel U-shaped bolt holding the cantilever arm of the overhead cables where the train draws power from.
Free shuttle bus services were activated as an alternative for affected commuters.