The opening of the new Tuas West Extension - a 7.5km, four-station addition to the East-West Line - will be delayed to the second quarter of next year.

The extension, which will connect to Joo Koon MRT station, currently the most western stop on the line, was scheduled to open at the end of this year.

The Land Transport Authority (LTA) said yesterday that more time will be devoted to "testing and fine-tuning" the extension's signalling system.

The extension uses the newer Communications- Based Train Control (CBTC) system. This is still being installed and tested on the rest of the East-West Line, which uses an older fixed-block system.

The CBTC will be rolled out on the East-West Line in 2018.

Yesterday morning, the media was shown around the Gul Circle MRT station, the first stop after Joo Koon.

LTA's director for rail systems, Mr Yee Boon Cheow, said civil, electrical and mechanical works for the four stations have been "substantially completed".

The Gul Circle station features a stacked viaduct design. Instead of eastbound and westbound tracks facing each other across a platform, one is above the other.

Adrian Lim