Train service between Joo Koon and Tuas Link stations was suspended on Thursday (Nov 16) for the authorities to carry out investigations, after two trains collided on Wednesday.
Bus bridging services were provided for affected passengers.
Commuters should also expect trains on the North-South and East-West lines to arrive at slower intervals, the authorities said on Wednesday.
The current two-minute interval between trains will be slowed down to between 2½ minutes and three minutes.
The Land Transport Authority (LTA) said that this was being done as an interim safety precaution after Wednesday morning's collision, which left at least 29 people injured.
"We want to make sure we understand fully what the cause is and that we have the right measures in place. Once we know that, we will be able to revert back to the previous... operations," LTA's deputy chief executive for infrastructure and development Chua Chong Kheng said at a press conference.
In a tweet at 4.43am on Thursday morning, SMRT said free bus services were available between Joo Koon and Tuas Link stations. It also said that trains were running as per normal on the North South Line.
Investigations so far found that a glitch in the new communications-based train control system wiped out a safety software feature when the first train passed a faulty circuit.
The French firm which provided the signalling system, Thales, said that this was the first time such an incident had happened.
PRIORITY FOR PASSENGERS' SAFETY
Our key focus after the incident had happened was primarily the safety and well-being of the passengers. So, we had to put in place our plan to send our Care teams, activate our management, so that the passengers who have sustained injuries can be attended to and taken care of immediately. That was our key priority at that time.
MR ALVIN KEK, SMRT Trains senior vice-president of rail operations (North-South, East-West lines), when asked why it took almost three hours for SMRT and the Land Transport Authority (LTA) to issue a statement about the incident.
This issue does not exist on the North-South Line. We are very confident that the system is very safe.
MR PETER TAWN, French firm Thales' spokesman, when asked if commuters should be concerned about safety given that the new signalling system is being used on North-South Line now.
"In fact, the CBTC (communications-based train control) is on record as one of the safest systems. We have never actually had a collision," said Thales representative Peter Tawn.
He added that it was unlikely, but the company has not ruled out increasing the safety factor - or the buffer distance - between trains, and a decision would be made once the investigations are completed.
The current safety factor ranges from about 10m to 50m, and is calculated based on a number of parameters, including the gradient of the track, Mr Tawn explained.
In Wednesday's incident, the trains had adhered to the safety buffer of 10.7m before the train at the back lurched forward and collided with the one at the station platform.
SMRT's senior vice-president of rail operations for the North-South and East-West lines, Mr Alvin Kek, said that the operator was putting "additional checks and controls in place" as a safety precaution.
"We have told train captains to be a lot more vigilant... even if (the train is) driven in the automatic mode," he added, saying that drivers are trained to deal with such emergencies.
Additional information will also be made available to drivers in their train cabins to help them assess such situations better.
LTA added that trains will also go through an additional layer of control measures and manual checks before they are deployed.