Work is proceeding apace to swop the ageing timber sleepers on the East-West Line with more durable concrete replacements that have double the life span. The track renewal project to replace more than 92,000 timber sleepers will speed up from tomorrow, with some stations closing half an hour earlier so the crew can get to work. With the extra time, they can replace 44 to 56 sleepers in a night, compared with 35 to 45 without it. The early closures will last till the end of this year, and the project is on track to be completed by the end of next year. The sleepers on the North-South Line have already been replaced. Sleepers are used to hold the tracks in place, and are transported and hoisted onto the tracks by road-rail vehicles. Rail operator SMRT now has a larger fleet of the vehicles, which will also help speed up the work.