Downtown Line Stage 2 (DTL2) is a 16.6km-long fully automatic, driverless underground mass rapid transit system in Singapore. Currently under construction, DTL2 will operate between Bugis station on the East-West Line in the centre of the city to Perit station on the Bukit Panjang light rail transit in the north-western region.
The project will significantly save the travelling time of the commuters who currently depend on bus transport in Bukit Timah, Upper Bukit Timah and Bukit Panjang areas. The light rail will reduce travel time between the two stations by 30% and benefit more than 60,000 students in the Bukit Timah Corridor.
Estimated to cost S$803m ($644.5m), DTL2 broke ground in July 2009. The project was initiated by the Land Transport Authority (LTA) of Singapore and is the second stage of the 42km-long Downtown Line (DTL), which was approved in 2007.
The DTL is being constructed in three stages. Stages 1 and 2 are under way construction and targeted for opening in 2013 and 2015 respectively. Stage 3 is scheduled to start construction in the second quarter of 2011 and targeted to be completed in 2017.
Lines and routes
The DTL2 route alignment and station names were announced in July 2008 after completion of advanced engineering studies.
The DTL2 will begin from the centre of the city from Rochor and stop at Little India, Newton, Stevens, Botanic Gardens, Duchess, Sixth Avenue, Blackmore, Beauty World, Hillview, Cashew and Petir.
The stations have been named after the history and heritage of their surroundings with the intention that the station names would be easily remembered by passengers.
The DTL2 was formerly known as Bukit Timah Line (BTL). The project intends to create a direct connection between the north-western part of Singapore and the central business district (CBD) and the Marina Bay area via DTL1.
It will also provide direct access to the residents of Bukit Panjang and Bukit Timah to Orchard Road and Clarke Quay, which are currently not linked by the rail system.
DTL2 will interchange on the North-East Line (NEL) at Little India station and will provide a direct link from Bukit Panjang and Bukit Timah to Hougang, Sengkang and Punggol on the northbound route and to Chinatown and Clarke Quay in the eastbound direction.
Newton station on the North-South Line (NSL) will provide interchange access to City Hall and Marina Bay on the southern track and to Toa Payoh, Bishan, Ang Mo Kio, Yio Chu Kang and Yishun on the northern track.
The interchange station at Botanic Gardens on the Circle Line (CL) will create a direct link to Holland Village, Kent Ridge, West Coast, Pasir Panjang, Telok Blangah and Thomson.
The DTL2 route will have 12 stations, of which nine will be newly constructed under nine different contracts.
The project features a new Gali Batu Depot which stretches from Kranji Express Way junction to Kwong Hou Sua Teochew Cemetry along the Woodlands Road. DTL2 trains will be stabled here. The depot will have a main workshop and four-storey administration and communication centre in addition to a locomotive workshop, a central warehouse, stabling siding building and a train wash building. Other facilities at the depot include ancillary buildings and sub-stations.
The Beauty World station will also be used as a civil defence shelter in case of emergencies.
In common with DTL1 and DTL3, all the stations on DTL2 will have platform screen doors, lifts, heavy duty escalators with energy saving features, tunnel ventilation and fire protection systems.
Lifts installed at the new stations will not have a machine room next to the lift shaft. Unlike conventional lifts, these new lifts provide better use of space within the station area.
Signalling and communication
DTL2 will be equipped with automatic train operation and automatic train supervision (ATS) systems. The communication system includes SIRUS Communication Based Train Control (CBTC) solution for automatic train control, WESTRACE electronic interlocking and Systematics ATS.
Bombardier Movia cars will be operating on DTL2. These will be three car set trains and will run on 750V DC third rail power system.
In 2008, LTA awarded a S$123.3m ($99m) comprehensive signalling and communication contract to Invensys Rail. The contract involved signalling and installation of communication equipments at all three DTL stages. Singapore Technologies Electronics will install the signalling systems for Invensys Rail under a sub-contract valued at S$28.7m ($23m).
A fleet of 73 fully automatic Bombardier Movia cars were contracted in 2008 for a sum of S$570.7m ($458m). These trains will be operated on DTL1, DTL2 and DTL3 as well.
Otis Elevator Company (Singapore) is providing platform lifts under a comprehensive DTL contract. Valued at S$22.7m ($18.2m), the contract involves supply, installation and commissioning of 108 lifts at 34 stations of the DTL project.
Heavy duty escalators are being supplied by Constructions Industrielles de la Mediterranee (CNIM) for a sum of S$100.3m ($80.5m).
Track laying work on DTL2 is being carried out by Alstom under a common contract awarded by LTA in February 2009. The contract calls for the design, supply and installation of 70km tracks for DTL1 and DTL2. Alstom will also be responsible for supplying 750V third rail DC power. The total value of the contract is $238.5m.
In September 2009, LTA awarded 10 design and construction contracts specific to DTL2 stations.
The contract for the design and construction of the new Gali Batu Depot was awarded to a joint venture of GS Engineering and Construction and Hock Seng Infrastructure. KTC group carried out the earthworks while the actual construction is being carried by CPG Corporation under a sub-contract worth S$350m ($280.9m). Construction of the depot is scheduled to be completed by 2015.
Design and construction contract of the stations in Bukit Panjang and the associated tunnels was awarded to Lam Chang Building Contractors.
Hillview and Cashew stations in the Upper Bukit Timah area are being designed and constructed by GS Engineering and Construction and Tiong Seng.
Tunnels between Beauty World and Hillview stations are being constructed by SK E&C. Cut & cover box method is being used to facilitate the tunnel construction.
The Beauty World station located at Upper Bukit Timah Road is being constructed by McConnell Dowell. The contract also involves design and construction of two 1,100m-long tunnels. These tunnels will have a diameter of 5.8m, two cross passages and 135m of cut and cover tunnel. McConnell Dowell has sub-contracted the station foundation work to Double Wong Foundation of Singapore.
The contract for Sixth Avenue, King Albert Par and Tan Kah Kee stations has been awarded to Singapore branch of Alpine BAU. The design and construction contract is valued at S$670.4m ($538m) and includes construction of 5.72km-long tunnel with 44m cut & cover box.
The Botanic Gardens, Steven stations and associated tunnels will be built by Sembawang Engineers & Constructors while the Newton station and tunnel work has been awarded to Shanghai Tunnel Engineering.
Design and construction of Rochor and Little India tunnels and stations situated along the Bukit Timah Road have been awarded to SsangTong Engineering & Construction Company who has in turn sub-contracted Mott Macdonald to execute the work.
Civil and structural services of the three underground stations and supervision of the depot construction is being carried by Meinhardt, an engineering, infrastructure and project management consultancy firm in Singapore.