SINGAPORE - In the past five years, there have been on average 20 cases each year of irregular speed changes or sudden acceleration of MRT trains, said Second Minister for Transport Ng Chee Meng in Parliament on Monday (Feb 19).
The LRT lines had about two such cases each year during the same period, he added in a response to Non-Constituency MP Leon Perera, who asked how often such incidents occurred, and if there was a mechanism for collating data on such occurrences.
Unexpected speed changes may occur because of temporary speed restrictions, put in place as a result of track maintenance or other renewal works being conducted.
Mr Perera also asked how often train doors closed without warning. Mr Ng said there were 125 cases of this occurring on the MRT network each year over the same period, and fewer than one case per year for LRT trains.
Commuter feedback is the primary source for these figures, he added.
The majority of such occurrences, of irregular acceleration and doors closing suddenly, were on the North-South and East-West Lines.
The two lines operate on an older fixed-block signalling system, in which train drivers are still responsible for opening and closing train doors.
"This introduces an element of human error," he said.
When the two lines complete their move to the new communications-based train control signalling system - already in place on the other three MRT lines here - doors will open and close automatically.
"Barring any unforeseen developments, we are on track to complete the resignalling programme this June," he said.
Mr Ng said earlier closures and later openings, as well as partial line closures, on the two lines over the weekends since December last year (2017) have helped speed up upgrading works.
Together, the shorter service hours have added the equivalent of 40 extra nights towards the installation and testing of the new signalling system.
Responding to a request by Mr Henry Kwek (Nee Soon GRC) for an update on the shutdown of lines to facilitate work, Mr Ng said the installation of noise barriers on the two lines has also been advancing at 1½ times its normal pace thanks to the longer engineering hours afforded by the closures.
He said the shortening of operating hours to facilitate other renewal works on the Republic's two oldest MRT lines was also being considered.
"We are studying how similar additional engineering hours can also help us speed up the renewal of other operating assets on the North-South and East-West Lines, such as the upgrading and replacement of the power supply system."