Costing an estimated THB61 billion, Bangkok’s MRT Purple Line was conceived as a solution to the travel and traffic woes faced by commuters in Nonthaburi Province, a densely packed urban center northwest of the Thai capital, Bangkok.
When completed, it is estimated the new metro rail line will take some 50 000 passengers off saturated roads during rush hour.
As a leading designer of rail infrastructure, Aurecon has for the past eight years worked closely with the Mass Rapid Transit Authority of Thailand (MRTA) and Italian-Thai Development (ITD), to oversee the design, planning and construction of the track works for the Purple Line.
“Once operational, the Purple Line will help ease traffic conditions and provide residents in Nonthaburi Province with a quick and convenient means to travel to and from the central and southern parts of Bangkok. Aurecon is proud to be associated with this landmark project that improves the lives of Thai residents. In the coming years there is further economic, transit-oriented development scheduled in Thailand and this project positions us well to be able to support the many upcoming projects in this area,” said Sakorn Kruemai, Country Manager of Aurecon in Thailand.
Design and construction work has been completed for the 23 km of elevated tracks and 16 stations, as well as for a 330 m bridge across the Chao Phraya River and a 3-storey depot building. The Purple Line’s headquarters is home to a train depot, train stabling building, workshop, car park and office space.
Aurecon’s commission with ITD started in November 2012, when the company was called in to consult on trackwork design services, including the track plinth and slab design, the selection of track components (the fastening and third rail system), and stray current protection design. The company also contributed its expertise to the rail structure interaction analysis.
As part of its work on the design, Aurecon designed in complying with specification of project specifying ballastless tracks throughout. Although this track structure is a higher capital cost when compared with traditional rail track design, it has the advantage of significantly reducing the need for frequent maintenance, which in turn reduces overall lifetime costs and operational disruptions.
Unlike conventional tracks, ballastless tracks are supported on a continuous slab of reinforced concrete with robust stress resistant properties. By comparison, traditional track designs require frequent maintenance because of the wear and tear that the welded rails and supporting sleepers experience.
The bridge was designed by MRTA’s project consultant and constructed by a local civil works contractor. For Aurecon, its work on the bridge included the analyses of the trackwork over the bridge, plus the design of the ballastless track, which was then constructed by ITD. Aurecon’s analyses made up a crucial part of the bridge project, by determining the need for, and the location of, the rail expansion joints.
Initial services will be with a three-car train, which will increase to six-car trains in the future. Construction work on the Purple Line has been successfully completed and passenger operations began in August 2016.