SMRT aims to complete sleeper replacement programme by 2016

Expect smoother, more reliable rides once sleepers replaced: SMRT

By Monica Kotwani, Channel NewsAsia, 29 Nov 2013

SMRT has said commuters can expect a more reliable system and smoother rides when all 188,000 timber sleepers along the North-South and East-West lines are replaced with concrete ones by 2016.

Sleepers are rectangular pieces of timber or concrete that hold the rail in an upright position and maintain the distance between the rails.

SMRT said it has currently replaced about 10 per cent of the sleepers, of which eight per cent consists of temporary timber to timber replacement which needed urgent replacing. These were done from November 2012.



Since August 2013, SMRT started permanently replacing timber sleepers with concrete ones with the help of special vehicles.

The concrete sleeper replacement has so far been done along the Marsiling and Sembawang tracks. Concrete sleepers are being used as they have a lifespan of about 50 years, double that of timber sleepers.

For the sleeper replacement work at the Marsiling and Yew Tee tracks, work starts after the last train leaves Kranji MRT station at around 1am.

Workers and their supervisors assemble at the Temporary Storage Area, which is not far off from the station. It is also where the concrete sleepers and the Road Rail Vehicles (RRVs) are kept.

Getting the RRV onto the rail requires skill and precision.

A worker has to carefully align the vehicle's steel wheels onto the rail before lowering them. As he does, the vehicle's rubber tyres will be raised. As its name suggests, the Road Rail Vehicle can run on both road and rail.

Once the vehicles are loaded, workers leave for the worksites travelling on foot along the tracks, with some 190 men divided between the Marsiling track and the Yew Tee track worksites.

Once at the respective worksites, the RRV unloads the concrete sleepers and places them onto the tracks, underneath the rails. The workers then ensure the concrete sleepers are spaced out evenly.

The actual process of changing the sleepers happens within a short frame of time. After all the loading and the preparations, the workers often have only about 1 hour to 1 hour 15 minutes for the actual process of changing the sleepers.

Work has to be completed by 4:30am, just half an hour before trains start operating.

"The basic challenge is to replace these in such a condition that there will be no safety risk to passengers or the system,” said SMRT principal engineer Lee Kim Ming.

“But equally important will be to ensure that service is not disrupted as a result of the work not being able to be completed on time, and then people being delayed in getting to work.

“On top of that, sometimes under (certain) climatic conditions, there may be heavy rains, there may be lightning. Under those conditions, obviously work also cannot be carried out."



SMRT said on average, about 30 to 40 sleepers can be replaced by an RRV each night. It currently employs about four vehicles, but hopes to have 12 vehicles by April 2014 to speed up the process.

Mr Lee said the work does tend to get noisy as heavy machinery is involved.

He said: "One of the ways we have reduced the noise is by installing the temporary acoustic screen, which seals off at the source certain parts of the noise. We are also in talks with the authorities to put in place permanent noise barriers which will also seal off the noise."




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