ABSTRACT
The Downtown Line stage 2 (DTL2) runs along the Bukit Timah Road / Upper Bukit Timah Road corridor with a route length of 16.6 km, 12 stations and a depot. The corridor is heavily built up with development on both sides of the existing road reserve. The Bukit Timah Road / Upper Bukit Timah Road corridor is congested with heavy traffic. The corridor has lots of greenery and mature trees. In addition, there is an existing canal with an approximate width of 6m ~ 10m over the southern section of the corridor.
The planning and design of DTL2 would need to take all these into consideration and to minimise impact to the built-up environment, and ensure it is buildable. The planning and design of urban railways is a complex process. This paper traces the design development of DTL2 and examines the main issues that are critical to the successful outcome of this project. It covers planning concept, the development of the railway alignment taking into consideration the site constraints, selection of station location based on planning intention, and evolvement of the station layout and entrances. These include the interfacing with government agencies on land use integration, connectivity and loading provision for future developments.
The paper also covers complex civil engineering challenges such as design and construction interfacing with existing and planned infrastructures, and adjacent existing developments in varying underground conditions. This includes considerations and major factors that determined the tunnel longitudinal profile and method of construction.
Keywords: Planning considerations, Design development, Challenges.
