The Tuas West Extension will open on June 18, extending the East-West MRT Line (EWL) into the Tuas area with four new above-ground train stations.
But the journey from the current EWL to the new 7.5km section - with Gul Circle, Tuas Crescent, Tuas West Road and Tuas Link stations - will not be entirely seamless for now.
Trains headed for the extension will have to stop for "a couple of minutes" at the Joo Koon station - currently the EWL's last stop in the west - to switch to a new signalling system, said the Land Transport Authority (LTA).
This switchover will cease next year when the rest of the East-West Line is upgraded with the same signalling system.
All trains on the North-South Line (NSL) and EWL are fitted with equipment that can now run on both the old and new systems, the LTA told The Straits Times.
The new signalling system is expected to be operational first on the NSL later this year. The system is now undergoing full-day tests on Sundays.
The new system can track the location of trains more precisely and allow them to travel more closely to one another. Trains can arrive at intervals of 100 seconds, instead of the current 120 seconds.
The new extension is expected to serve 100,000 commuters daily, and those working in the Jurong and Tuas industrial estates can look forward to "significant time savings", the LTA said.
Giving an example, it said a journey from Ang Mo Kio to Tuas West can be cut by about 35 minutes, from about 100 minutes currently to 65 minutes.
Before the official opening of the extension, an open house will be held on June 16, during which the public can preview the four new stations from noon to 8pm.
They can also take free train rides along the Tuas West Extension during the open house.
Besides the four stations, the Tuas West Extension project also includes the construction of the Tuas viaduct, which opened in February.
The viaduct was built in anticipation of heavier traffic that will come with developments in the western part of the island, such as the Tuas port.