Update: Train services on the North-South Line were disrupted from Kranji to Woodlands station towards Marina Bay on Tuesday (April 26) at about 6.30am due to a traction power fault, said rail operator SMRT. Services were resumed about 10 minutes later, said SMRT in a tweet.
In a Facebook post at 8.30am, SMRT said it is investigating the cause of Tuesday's fault to see if it is related to the one the night before.
SINGAPORE - SMRT has apologised for the train service disruptions that affected more than 20 MRT stations during peak hour on Monday evening (April 25).
SMRT tweeted that services on two lines - East-West Line and North-South Line - were restored at about 8.25pm.
However, SMRT said in a Facebook post that it is still working to recover services on the Circle Line and Bukit Panjang LRT.
"Four trains on the BPLRT were stalled between stations and 150 passengers were safely detrained," SMRT wrote.
It explained that the "traction power fault" has been "traced to a power dip at the Buona Vista power intake station".
"We are currently investigating the cause of the power trip.
"We deeply apologise for the inconvenience caused."
Earlier, there was no train service between Joo Koon and Bugis stations on the East-West Line, and Woodlands and Jurong East stations on the North-South Line.
Some MRT stations also experienced blackouts, according to updates by Twitter users.
Reader Hwa Heng sent photos of the power failure to citizen journalism website Stomp via WhatsApp and said: "The lights (kept) going on and off."
"Just now the air-con stopped too but at least it's returned so we can have some ventilation."
The train operator offered free bus services between Joo Koon and City Hall stations, and between Kranji and Jurong East stations.
These free bus services have since ceased.
SMRT expects "crowding at some stations and congestion as trains are travelling at a lower speed".