Train operators have to inform commuters of any delay that exceeds 10 minutes, by announcing it on the train and at the station, said the Land Transport Authority (LTA) yesterday.
If the delays worsen, operators are expected to also broadcast this via mainstream and social media such as Twitter and Facebook, it added in a statement.
The regulator outlined these existing requirements following queries from The Straits Times about recent commuter complaints that operators weretardy or failed to make announcements during disruptions.
Said its spokesman: "We have received feedback from commuters on rail operators' public announcements during service delays, and will be looking into this matter."
Rail operator SMRT received flak on social media from commuters in recent months that delays were not being announced.
The most recent case was a train fault on the North-South Line in the morning rush hour on Nov 9. Commuters posted photos online of congested platforms at Admiralty, Ang Mo Kio, Woodlands and Yishun stations, complaining there were no announcements of a delay.
SMRT said it is improving its travel app, SMRT-Connect, to give commuters more accurate information. Mr Patrick Nathan, its vice-president for corporate communications, said the company is also piloting QR codes at stations to give commuters information on bus options during disruptions.
"We recognise and understand the need to notify commuters of any incidents that may affect their travel experience," Mr Nathan said, adding that SMRT will alert commuters of delays longer than 10 minutes through various channels.
Operators SMRT and SBS Transit have to adhere to a code of practice on incident management that the LTA initiated in 2012.
Experts said SMRT needed to be prompt and transparent in announcing delays.
Mr Lars Voedisch, managing director of PRecious Communications, told ST: "You could argue that they should share more information at earlier stages of possible delays. But, at the same time, they also shouldn't overload the public with information that only has a minor impact."
National University of Singapore transport researcher Lee Der-Horng noted that commuters farther down the line from a train fault may experience a longer wait than what operators announce, because disruptions result in congestion across the network and this takes time to ease. "Train operators thus need to find a way to customise their alerts to commuters at different stations," Dr Lee said.