Last Tuesday night, when SMRT had to shut down the two lines which are the backbone of the train system, thousands of commuters spilt out of the exits of 54 stations.
Others arrived to find the stations closed during the breakdown of the East-West and North-South lines, which lasted more than two hours and affected more than 250,000 commuters during the Tuesday evening peak hour.
Many who were left stranded in unfamiliar neighbourhoods took more than two hours to get home as they tried to figure out alternative ways to complete their journeys.
Despite a series of recommendations by the Committee of Inquiry in 2012 following two major breakdowns in 2011, the problem of dealing with commuters in the aftermath of a breakdown remains.
The COI had noted, in particular, that improvements to bus bridging must be made to help stranded commuters. It recommended that SMRT consider designating dedicated bus pick-up points and have bus-bridging services at unaffected MRT stations.
However, on Tuesday, SMRT did not activate this bus-bridging service. Instead, it said, it deployed any available bus resources to supplement regular bus services which were free to commuters.
SMRT has acknowledged this was one of the gaps in its service recovery that evening.
Experts agreed that additional buses that evening could have been better utilised to disperse the crowd. A more effective way would have been to arrange for buses to take commuters to transport nodes, including bus interchanges, where commuters will have more bus services to choose from.
"These buses should take passengers to designated centres, not run their regular routes - you could take (commuters) to neighbourhoods such as Buona Vista, Jurong East or Tampines," said Mr Jair Smits from engineering consultancy Witteveen+Bos, which also specialises in urban transport management.
Another good way to deploy the buses is to have them run parallel to the train line, noted National University of Singapore transport researcher Lee Der Horng. "This means people can still use it in lieu of the MRT," said Prof Lee.
Other experts, such as Professor Lau Hoong Chuin of the Singapore Management University (SMU), suggested using existing transit card data to understand commuters' travel patterns at different stations and plan shuttle buses accordingly.
"You can very quickly optimise your bridging services. For instance, during office hours most commuters will be going to Raffles Place. So if Ang Mo Kio has a disruption, you will want to take commuters to Raffles Place," said Prof Lau, who is director of the Fujitsu-SMU Urban Computing and Engineering Corp Lab.
MP (Mountbatten) Lim Biow Chuan, who is on the Government Parliamentary Committee for Transport, noted however that it was not economically feasible for public transport operators, SMRT and SBS Transit, to have too many buses on standby in depots.
"The struggle we have is how many buses do we want to put on standby, do we plan (contingencies) on the basis of one, two or three MRT lines being down?" he said.
To solve this problem of redundancy, experts suggested roping in private bus operators to fill in the gaps during a major breakdown.
Woodlands Transport's general manager Roger Wong, said his company with about 350 buses, would be happy to provide assistance.
"As a home-grown private transport company, we are committed to serving the local community," he said.
Additional reporting by Cheow Sue-Ann
