A software update installed late yesterday evening is expected to address "teething issues" that surfaced during tests of the new signalling system on the North-South MRT Line, leading to train service disruptions for commuters.

Developed by French firm Thales - the contractor in charge of the resignalling project - the update is expected to improve the alignment between train and platform screen doors, boost trackside-to-train communications and strengthen the signalling system's main server.

The software update has undergone "rigorous testing" in a simulated environment as well as on the North-South Line and the Tuas West extension.

The new signalling system is meant to allow trains to run on a communications-based system, instead of the older fixed block system. This will allow for trains to run at shorter intervals of 100 seconds, instead of the current 120 seconds.

At a press conference yesterday, the Land Transport Authority (LTA) said that its engineers, rail operator SMRT and Thales will be on stand-by to "closely monitor" the transition during the software update and address any faults that may arise.

While a new signalling system can take up to a year to stabilise, LTA's chief executive Ngien Hoon Ping said it may be stable by the end of the year. Testing of the system started in March.

SMRT Trains chief executive Lee Ling Wee said the new signalling system was showing signs of improvement.

"While it may not seem like it, our data shows that delays due to teething problems relating to the new signalling system have reduced over past weeks," he said.

LTA and SMRT hope to start testing the new signalling system on the East-West Line during passenger service hours by December, so as to coincide with the year-end school holidays, when there are fewer commuters.

However, this is dependent on the stability of the system, noted Mr Ngien.

Implementation of the new system on the East-West Line will take place using a gradual approach, similar to that on the North-South Line, when the system was first tested during the last hour of passenger service, before being expanded to full-day tests on Sundays a month later, and then on weekdays the following month.

"We will make sure the lessons learnt from the North-South Line are ported over to the East-West Line," said Mr Lee.