Tunnelling begins for Circle Line's final stage

Works also under way to upgrade line ahead of CCL6 opening in 2025; LTA to buy 12 more trains

A tunnel boring machine being launched at Keppel station. The machine will tunnel from Keppel to the existing HarbourFront station on the Circle Line.
A tunnel boring machine being launched at Keppel station. The machine will tunnel from Keppel to the existing HarbourFront station on the Circle Line.PHOTO: LAND TRANSPORT AUTHORITY

Tunnelling works for Circle Line 6 (CCL6) - the final stage of the orbital Circle Line - started yesterday with the launch of a tunnel boring machine at Keppel station.

The Land Transport Authority (LTA) said yesterday that the machine will tunnel from Keppel to the existing CCL HarbourFront station. Two other tunnelling machines are expected to be launched in September and October this year.

The LTA said that work on CCL6 is progressing on track, with 66 per cent of earth retaining and stabilising structure works having been completed.

"Excavation works and construction of structures have also commenced and are progressing well," it noted. "Foundation and excavation works are also in progress at Kim Chuan Depot Extension."

The expanded depot will provide additional facilities to support the larger CCL network and train fleet of up to 133 trains. It will also have an above-ground bus depot which can accommodate 550 buses.

LTA said yesterday that it will also be buying 12 new trains from French supplier Alstom to cater for the expected increase in passengers on the line.

These trains will be delivered progressively from 2024, and are in addition to the 11 trains that were procured in April last year for CCL6. When these 23 trains are delivered, the total CCL fleet size will increase by 36 per cent to 87.

Meanwhile, works are under way to upgrade the CCL to prepare for the opening of CCL6 in 2025.

The LTA said it is working with operator SMRT on a series of system enhancements to the existing CCL.

The enhancements will allow the decade-old CCL to support, among other things, a larger train fleet when three new stations along CCL6 open. The upgrades include the line's signalling system; power supply system (including installation of a load-break switch at substations to help maintain continuity of power supply should there be a power outage); and communication system, to allow more seamless real-time communication between individual stations and the Operations Control Centre.

This will strengthen SMRT's oversight of the entire CCL system, the LTA said.

LTA chief executive Ngien Hoon Ping said: "As we are working on a 'live' railway system, we will work closely with SMRT to put mitigating measures in place to ensure daily operations will not be impacted."

The LTA said work on CCL6 is progressing on track, with 66 per cent of earth retaining and stabilising structure works having been completed.

 
 

Most of the work will be done during non-operating hours.

SMRT chief executive Neo Kian Hong said it is "essential that we start the renewal process early and apply the lessons learnt from the renewal of the North-South and East-West lines".

The LTA said construction of the three CCL6 stations - the Keppel, Cantonment and Prince Edward Road stations - and the expansion of Kim Chuan Depot are on track.

When CCL6 opens, the entire orbital line will have a total of 33 stations, with 12 interchanges.

The sixth and final stage of the Circle Line will cost $4.85 billion - more than half of what the first five stages of the current Circle Line cost. On a per-kilometre basis, the 4km CCL6 will cost $1.2 billion per km - or five times the average per-km cost of the first five stages spanning 33km.

The LTA attributed the cost escalation to various factors, in-cluding inflation.

A version of this article appeared in the print edition of The Straits Times on July 26, 2019, with the headline 'Tunnelling begins for Circle Line's final stage'. Print Edition | Subscribe