Rush-hour commuters in the west had their journeys disrupted yesterday morning when a westbound train on the East-West Line developed a fault.
The train limped to Commonwealth, where passengers were asked to disembark.
The incident caused a tailback effect, with the peak-period crowd growing exponentially by the minute at several stations.
To prevent people from entering already overflowing platforms, fare gates in at least one station were closed.
Stockbroker Cole Cheong said he did not hear any announcement at Boon Lay station, where the gates were closed.
"Hopped into a taxi," he said. "Sharing with strangers. And traffic on the AYE is very slow." AYE is the Ayer Rajah Expressway.
Normal train service resumed more than half an hour later at 8.36am, although SMRT said that longer travelling times were expected as it worked to clear the crowds at stations.
In a statement, SMRT spokesman Patrick Nathan said: "Passengers aboard an East-West Line train en route to Joo Koon were detrained at Commonwealth this morning due to a signalling fault affecting the train.
"The train was then moved to Ulu Pandan Depot for checks. As the detrainment took place during peak hour, there was a build-up of passengers at interchange stations such as Buona Vista and Jurong East.
"We are sorry for the inconvenience caused to passengers due to the additional travelling time."