TRANSPORT operator SMRT Corp expects to start replacing the East-West Line's power-supplying third rail next month.
The project will be undertaken by local contractor Gates PCM for $13 million. SMRT will call a tender for a similar project on the North-South Line soon.
Sagging sections of the third rail were singled out as the main cause of two massive breakdowns on the North-South Line in 2011, and SMRT had initially wanted the replacement to take place as early as last year. But the project was pushed back because of other more urgent works, such as replacing track sleepers.
SMRT chief executive Desmond Kuek said the operator was able to defer the replacement works largely because it had bought sophisticated equipment that could "detect third-rail failure on a real-time basis".
"This allowed us to free up limited track access to concentrate first on the more urgent replacement of the deteriorated sleepers," he added.
Sleepers are vital to safety as they keep the train tracks firmly aligned. SMRT has replaced 96,000 wooden track sleepers on the North-South Line with concrete ones, and is in the process of replacing 100,000 more on the East-West Line.
Meanwhile, work has started to replace the network's 30-year- old signalling system, which will allow trains to arrive as frequently as once every 100 seconds, compared with once every 120 seconds currently.
This so-called resignalling project will be completed on the North-South Line next year and on the East-West Line by 2018.
Together with the delivery of more trains, commuters can expect the morning and evening crush to diminish dramatically by the second half of next year.
Mr Kuek, however, said the higher service frequency may require a change in passenger behaviour. Currently, commuters pack each train to the brim, causing it to remain at a station for 20 seconds or more. This sometimes holds up subsequent trains, and negates the benefits of shorter service intervals that the upgraded system is capable of.
"I visited Taipei to see how they manage this, and interestingly they deploy service ambassadors to block people from boarding when it is time for train doors to close," Mr Kuek told The Straits Times.
"It's a new commuter behaviour that we will have to bring about when the shorter headways are in force next year."