An ongoing project to replace timber sleepers along the East-West Line with concrete ones has received a lift, with operator SMRT deploying gantry cranes to speed up the works.
The cranes allow road-rail vehicles - machines used to swop out sleepers which hold the tracks in place - to be deployed more quickly along the line.
This, in turn, allows more sleepers to be replaced every night.
Previously, an average of about 300 sleepers were replaced with more durable concrete ones each night. With the cranes in place, up to 200 more can be replaced.
The vehicles had previously been launched at stretches of the MRT track that are at ground level, such as the Ulu Pandan and Changi depots, and near the Kallang and Redhill stations. It could take up to one hour for them to reach distant worksites.
The fixed gantry crane near Pasir Ris will allow vehicles to be deployed more swiftly to the stations between Pasir Ris and Simei. It has been in operation since Jan 14.
The one near Chinese Garden will be used to replace sleepers between Jurong East and Boon Lay stations, and is expected to begin operations on Feb 14.
SMRT expects to replace all 92,000 sleepers along the East-West Line by early next year. More than 30,000 have been replaced so far. The project was slated for completion by this year, but has been pushed back after SMRT rescheduled its long-term track upgrade and renewal programme in the aftermath of a massive breakdown on July 7 last year that crippled the East-West and North-South lines. This was to give investigators track access to find the cause.
An earlier project to upgrade the 96,000 sleepers on the North-South Line was finished in April last year.
The sleeper-replacement project is one of several that SMRT has embarked on to improve the reliability of the ageing North-South and East-West lines.
SMRT said the upgrading of the signalling system,which will allow more trains to be deployed at shorter intervals, is currently 95 per cent complete on the North-South Line and 63 per cent complete on the East-West Line. The upgrading should conclude in 2018.
The operator will also finish replacing the third rail, which supplies electricity to trains, along both lines by early next year.
SMRT project director for track renewal, Mr Roger Lim, said the fixed cranes, which are also used to lift concrete sleepers onto the tracks, were chosen over mobile cranes for several reasons. For one thing, they are more stable and, hence, safer.
Mobile cranes also take longer to set up, which would eat into the three hours allocated every night for the replacement of sleepers.
The cranes, which stand at about 20m and weigh 74 tonnes, can safely lift up to 40 tonnes, the equivalent of more than 100 concrete sleepers.
Mr Lim said that commuters can expect slower train speeds for up to 1 1/2 months in areas where sleepers have recently been replaced.