Downtown Line (DTL) Stage 1 is a 4.3km-long, fully automatic and underground mass rapid rail line in Singapore. It connects Bugis station on the East West Line (EWL) with Chinatown station on the North East Line (NEL). The line is being developed and operated by the Land Transport Authority (LTA) of Singapore.

The S$12bn Downtown Line will comprise a 42km-long underground rail network with 34 stations. It is being constructed in three stages with a target to be completed by 2017.

DTL Stage 1 broke ground in February 2008 and was completed in 2013, while Stages II and III are scheduled to be completed in 2015 and 2017 respectively.

Project details of the Downtown Line Stage 1

"Downtown Line (DTL) Stage 1 is a 4.3km automatic underground mass rapid rail line constructed in Singapore."

Downtown Line Stage 1 was initially planned to cover a slightly less distance. The original plan was to build it as a 3.4km-long extension of the Circle Line, which starts from the Dhoby Ghaut station and ends at HarbourFront station on the North East Line.

The project was first announced in 2005 and was known as ‘Downtown extension of the Circle Line’.

Following the public hearing, LTA decided to extend the line by a further 0.9km to connect the Promenade station with Bugis station. The revised extension was announced in April 2007 and thereafter came to be known as Downtown Line Stage 1.

The project involved construction of six underground stations. The Bugis, Promenade and Chinatown stations serve as the interchanges on the East-West Line, Circle Line and the North East Line respectively.

Infrastructure of Singapore’s DTL 1

DTL Stage 1 has six stations, including the Bugis, Promenade and Chinatown interchanges. The other three stations are Bayfront, Landmark (in Downtown area) and Telok Ayer (near Cross Street).

The platforms of all the stations are equipped with automatic platform screen doors, lifts and elevators.

A maintenance and stabling depot is located at the northern end of the DTL Stage 2 to serve the fleet of DTL Stages 1 and 2. It is constructed near the Woodlands Road on 21ha of land.

Signalling and communications along the line

The signalling system is designed based on the train control moving block signalling technology, automatic train supervision and computer-based interlocking system.

Systems operations are remotely supervised and controlled using the integrated supervisory and control system (ISCS).

The communication system includes a number of subsystems such as the public address, radio and telephones, onboard signage systems and video surveillance.

Contracts awarded

The S$230.3m design and construction contract of the landmark station was awarded to Taisei Corporation.

Sembawang Engineers and Constructors constructed the Bayfront station in association with Soletanche Bachy, under a contract valued at S$463m.

Shimizu Corporation was responsible for the construction of the tunnel between Promenade station and Marina Bay, under a S$102.8m contract. Shimizu, in turn, sub-contracted the architectural works of the Promenade station to Incorporated Builders Group.

The developer of Marina Bay Sands Integrated Resort of May Bay area was contracted to design and build the northern end of the tunnel.

Cross Street station was constructed by a joint venture of Soletanche Bachy & Koh Brothers in co-operation with Samsung Engineering and Construction.

Soletanche Bachy & Koh Brothers were also involved in the construction of the Bugis station and associated tunnels. The Chinatown station was built by Gammon Construction. The total value of these two contracts was S$385.2m.

CPG Corporation was subcontracted by the joint venture of Soletanche Bachy & Koh Brothers to provide engineering, construction and management services for the tunnel construction near Bugis station.

The fibre reinforcement polymer solution for the tunnel boring machine (TBM) breakthrough was provided by FiReP. Accredited checking services were provided by Meinhard Group of Singapore.

Alstom installed the tracks and supplied the design and related equipment for the DTL Stage 1.

In addition, LTA has awarded few system wide contracts applicable to all the three stages of DTL.

A rolling stock contract was signed with the consortium of Bombardier Transportation and Bombardier Singapore for the supply of 73, three-car train sets for S$570.7m. The new fleet will be used on all the three DTL stages.

Westinghouse Brake and Signal Holdings supplied and installed the signalling system and platform screen doors. The ISCS and communication systems were delivered by Singapore Technologies Electronics.

Otis Elevator Company is responsible for the supply, installation and commissioning of 108 lifts. Constructions Industrielles de la Mediterranee (CNIM) will design, manufacture and commission 299 escalators.