SINGAPORE - The Land Transport Authority (LTA) and SMRT will be installing electrical breaks at Jurong East and Raffles Place Interchange stations.

This means that when the need arises, the North-South and East-West lines can be electrically disconnected and this will avoid the situation that occurred on July 7 when a fault could not be identified and both lines had to be shut down leaving thousands of commuters stranded.

Transport Minister Khaw Boon Wan wrote this in a blog on Thursday entitled "Avoiding another system-wide disruption".

He added that under normal operations, these breaks will not be activated as LTA and SMRT want to continue to have the flexibility with the system.

The two lines are electrically linked to allow trains to move from the NSL to the EWL, and vice versa.

The link was, and still is, essential as Bishan Depot on the NSL is the only depot across the two lines with heavy maintenance and overhaul capability. Other than for maintenance, allowing cross-overs gives operational flexibility. Unfortunately, this also means that a power fault on one line could affect the other, he wrote.

The electrical breaks will be fully installed by the end of next month.

"Meanwhile, maintenance of all lines must be stepped up, to avoid any disruption. This is active work in progress," he said.

Mr Khaw had attended a simulation exercise on Wednesday to test the operational readiness of the two operators in the event of a major breakdown.