The competitors are commuters disgorged by trains from Choa Chu Kang on the North-South line and those already on the platform at Jurong East.

The maelstrom hits a peak whenever a south-bound train from Choa Chu Kang pulls into the station at the same time as a city-bound train from Boon Lay.

Between 8am and 9am yesterday, hundreds of commuters from the south-bound trains surged towards the east-bound ones. Office workers and students shoved their way on board, but without any ugly scenes.

Still, each time an east-bound train pulled away, up to 300 people would be left behind on the platform to await the next train.

One of them was bank officer Bryan Wong, 35, who travels to the City Hall station to get to work. He is resigned to letting one or two trains pass every day.

Referring to what he called 'overwhelming' crowds, he said: 'It may be very uncivilised, but sometimes you really have to push your way to get in.'

Yesterday was the first day additional train trips were added elsewhere to the train network to ease congestion.

But Jurong East won't get this relief, rail operator SMRT explained, because the track layout and high frequency of train arrivals at this interchange posed technical difficulties.

In yesterday's check, eastbound trains arrived every two to three minutes and south-bound trains, every four to five.

But commuters, even those at other stations, felt trains should arrive more frequently.

Miss Loh Wai Leng, a 35-year-old manager waiting at Paya Lebar station, said that in Japan, two trains would arrive every minute during peak hours.

Another suggestion was to give passengers more time to board and alight.

Mr Jonathan Choo, 26, who is doing his pupilage at a law firm and who was waiting at the Toa Payoh station, said: 'Sometimes it's not a matter of not being able to squeeze in, but rather, the doors close too soon.'

Customer service representative Eileen Koh, 23, who was at Jurong East, suggested that train operators make regular announcements to remind commuters to move to the centre of the carriage or even hire officials to herd people onto the trains.

'No one can get in because no one is moving in. Then people end up missing the train for nothing,' she grumbled.

Added Miss Koh: 'Passengers should learn to make way for others to board the train, and be less selfish.'

ADDITIONAL REPORTING BY YEO GHIM LAY AND APRIL CHONG