SINGAPORE - The Circle Line is in its third day of disrupted service on Wednesday (Aug 31) after a signalling problem was first reported on Monday.
Rail operator SMRT has been tweeting since Tuesday evening that commuters should expect a longer journey. It has also warned that intermittent braking may occur and commuters should hold onto handrails for their safety.
SMRT has said that a signalling fault involving wireless communication between the train and the track is to blame.
"Initial investigations point to possible signal interference in tunnels causing loss of signal between the trains and stations which our engineers are trying to confirm," said vice-president for corporate information and communications Patrick Nathan in response to media queries.
Mr Nathan said SMRT has been investigating the fault since Monday.
He added: "While services continue to run, as a precautionary measure and to minimise delays, staff continue to be stationed on board all trains for quicker service recovery. More staff have also been deployed to stations to assist passengers."
At 12.44pm, SMRT tweeted that normal service had resumed on the Circle Line, but followed up an hour later with a new announcement that journeys might still take up to five minutes longer.
SMRT originally sent out a tweet at 6.47am on Wednesday warning commuters to expect an additional three to five minutes of travelling time.
At 8.40am, it sent out another tweet saying that the additional travelling time was 10 minutes.
Then, from 9.41am on, SMRT said that commuters could also expect additional waiting time at stations.
Commuters again took to social media to express their frustration and dismay, reporting stalled trains and long intervals between trains during the morning rush hour.
One user, Patrick Khaw, punned on Korean zombie movie Train To Busan and wrote: "Am stuck in the train tunnel on the Circle Line between Caldecott and Botanic Gardens! Reminds me of the movie 'Train to Bishan'."
There were similar complaints on Tuesday morning as the signalling fault that disrupted service on Monday persisted, according to SMRT. It had been conducting tests and investigations since but the issue has yet to be resolved, Mr Nathan told The Straits Times on Tuesday.
Mr Nathan said then the fault has been identified as a fault in wireless communication between signalling equipment on the train and on the track.