The man, in his mid-40s, was hit at Choa Chu Kang station on the North-South Line at about 8am.

He fell onto the tracks and was pinned under a train carriage, and his body had to be extricated by Singapore Civil Defence Force officers.

Police are investigating the case as one of unnatural death.

The incident affected about 7,300 commuters, many of whom were on their way to work.

Within about 20 minutes of the incident, train operator

SMRT had deployed 12 buses to ferry them for free from Yew Tee station to Bukit Gombak station, said a spokesman.

People who could not wait walked at least part of the way from Yew Tee to Bukit Gombak, which are almost 5km apart.

'I thought there was some sort of a procession going on,' said shop assistant Lim Yee Yen, 36, who took one of the trains headed in the opposite direction, which continued to run.

Safety consultant Sam Hafez, 55, decided to try and get a taxi, but wound up waiting almost two hours for one to get him to his office at the Biopolis in Buona Vista Road.

Mr Hafez said: 'My boss called me up and asked why I was late.'

According to the Land Transport Authority, the number of track intrusions has risen from an average of 16 cases a year in 2004 and 2005, to 30 in 2006 and 31 last year.

To slam the brakes on the increase, the Government announced in January that it will install screen doors on the platforms of all above-ground stations.

The doors will first be installed in Jurong East, Pasir Ris and Yishun stations next year, with the other stations ready by 2012.

Passengers who were unable to complete their journeys due to yesterday's incident can get refunds from any of the 51 train stations until Thursday.