Bangkok Transit System Light Rail Route Extension, Thailand

When the Bangkok Transit System opened in 1999, it was a turning point in the fortunes of the capital of Thailand. The densely populated city was crippled by appalling road traffic congestion that stifled business life and causes some of the world's worst air pollution. Despite the system being laden with serious debts because of initial lower than expected ridership, following political debate, further extensions to the network were announced in September 2006 by Thailand's then Prime Minister Thaksin Shinawatra.

A massive 82% of the city's journeys during the early 1990s were by bus, car motorbike or taxi, and average vehicle speeds in the centre dropped to as low as 10km/h (6mph).

The cost of building the first phase of the system was US$1,800m (£1,100m), which is almost twice that of a comparable line in Manila, Philippines. Lending banks were promised 680,000 passenger journeys per day (a 16% rate of return), but early traffic figures of about 105,000 passengers per day were only just covering operating expenses

The reason for the low ridership is the high cost of fares, which are three times the parallel bus service.

THE PROJECT

In an effort to provide a long-term solution to road congestion, Bangkok Metropolitan Administration (BMA) initiated three separate mass transit system schemes. BTS is an elevated heavy rail system running above the business district.

Tender documents for a turnkey system were issued in March 1993 to five interested consortia, and in July the following year, the Siemens-Italian Thai consortium signed up to build and operate the line. This agreement was later amended to cover maintenance as well.

With the rapid changes in transport plans for Bangkok and frequent debate over alignment and concept, the Government is in discussion to establish a regulatory agency to monitor all transport across the city and co-ordinate services. This agency's work will include regulating the development of BTS.

INFRASTRUCTURE

The network comprises two lines, extending to a total of 23.1km. The Sukhumvit line is 16.8km long, and runs from On Nut to the Mo Chit bus terminal. The Silom line, meanwhile, runs 6.3km from the National Stadium to Sathorn Bridge, on the banks of the Chaopraya River.

These lines intersect through the city centre, and both have an interchange at Central station, the main heavy rail terminus.

Trains run on dual tracks, fixed directly to concrete plinths, carried on a 9m-wide viaduct. The plinths are supported on single box viaduct girders, each 12m above the road level. The concrete foundations have been piled underground to a depth of 50m.

From contract signature to the operation of the first service trains took four-and-a-half years, a remarkably short time given the scale of the infrastructure works, and the busy nature of the city amidst which they worked. On opening, the system operated a minimum two minute interval service.

The new extensions to the network involve the construction of two all-new routes and extending Blue Line in both directions. In total this round of construction will increase the system length by 90km. The first new route is Red Line, which will be a 40km alignment running from Phya Thai to Rangsit and Chiang Pak Noi. Second is the Purple Line, which will run 23km from Bang Yai to make a connection with Blue Line at Bang Sue. The extensions to Blue Line will see it increase in length by 27km – 14km from Hualampong to Bang Khee, and 13km from Bang Sue to Tha Phra.

ROLLING STOCK

In total 35 new three-car trains have been built for use on the system. Each train is 65.1m long, and can carry up to 1,100 passengers. The three-car trains can be doubled in length at peak times. Power comes from a third conductor rail, supplied at 750v dc.

Each car is air-conditioned and connected to adjoining cars by inter-car gangways. Regenerative braking is fitted.

The train sets and on-board equipment were tested in Europe before shipping, to ensure a smooth commissioning process. Each train is fitted with Siemens IGBT-3 three-phase traction control for optimum delivery of power to the driving wheels.

SIGNALLING/COMMUNICATIONS

While drivers man most trains, automatic train control systems allow units to take into account the status of the line ahead, with speeds adjusted to take into account prevailing conditions. The engagement of a single consortium to build the infrastructure and rolling stock has resulted in the ability to ensure maximum compatibility between the trains and other fixed equipment.

THE FUTURE

The Thai central government has granted 7 billion baht to cover 60% of the cost of two Skytrain extensions on the condition that BMA constructs Southern Bangkok Transportation Center (Taksin Center) and sets up a joint ticketing system with the subway, expressway, Mahachai Railway and other modes of transporation. BMA wants to extend the northern route from Mochit to Saphan Mai (Ying Charoen flea market - 16km) as a line to Ratchayothin would not meet the local demand. Senanikhom Flyover must be torn down to make a way for the extension.

The Taksin extension (2.2km, two stations, 1.1 billion baht) and Samrong extension (8.9km, six stations, 8.4 billion baht) both received approval in February 2000, but are still incomplete.

BMA is also working on feasibility studies for a 4km Paholyothin extension to Mochit and Kasetsart University, and 7.9km Paknam extension from Samrong Tai to Downtown Samut Prakarn.

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