Bangkok's first underground metro open: Bangkok's second rapid transit project, the so-called Blue Line underground metro, is expected to open this month. The Blue Line should help to ease considerably traffic congestion in this huge city

International Railway Journal, July, 2004

CONSTRUCTION of the 20km 18station Chaloem Ratchamongkhon or Blue Line began in 1997 when the Mass Rapid Transit Authority of Thailand (MRTA) awarded five contracts for construction of the northern and southern parts of the line, each 10km long. These contracts included civil works, construction of the depot, lifts, escalators, and the trackwork including the conductor rail.

As a sixth contract, MRTA signed a concession agreement with Bangkok Metro Company Limited (BMCL), with the stipulation that BMCL was to provide a major portion of the equipment. This subsequently led to the award of a contract to Siemens Transportation Systems to supply the mechanical and electrical railway equipment and services. This was financed by Thai banks to the tune of 352 million [euro].

This is the second turnkey project in Bangkok that Siemens has been involved in, the first being the SkyTrain two-line elevated metro that opened in 1999. There will be three interchanges between the two systems.

Siemens was awarded the Blue Line contract in December 2001, four years after construction of the metro had started. At that time, most of the civil works had been completed--the line consists of twin-bore tunnels. In addition, the above-ground depot, designed to accommodate up to 170 three-car trains, mad the administration buildings had been built by the concessionaire.

When Siemens was due to start work in February 2002, a project execution time of only 29 months was envisaged. At the request of the Thai government, BMCL and Siemens Transportation Systems agreed to an accelerated programme intended to cut the project duration by three months to 26. Even so, trial operation of the new system started on March 1, only two years after Siemens started work on the contract.

In view of the short time available for completing the project, the on-schedule start of trial operations is an outstanding achievement. Altogether, around 60,000 data signals related to the signalling had to be integrated in order to enable problem-free operations of the metro service from the operations control centre.

The reduced time available for completion of the project made it necessary to employ a maximum of 1500 people when the workload peaked. Adherence to the tighter deadlines and rapid setup of the maintenance service was made possible largely by using experienced staff taken over from the SkyTrain project.

At the request of the Thai government, the first train was air-freighted from Vienna to Bangkok, with arrival of the last car of the three-car train being greeted by an official ceremony at Bangkok's Don Muang international airport on October 15 2003. The last train left the manufacturing plant in Vienna on schedule on February 9. "The first demonstration run began on April 13.

The Siemens contract consisted of project management and integration of all the electromechanical system elements, as well as the supply of 19 three-car metro trains. Also included was the system for supplying power from the 69kV national grid, signalling and safety systems for automatic train operation and supervision, all telecommunications, the remote control and operations control system, platform screen doors, the automatic fare collection management system, depot and workshop equipment, and all the signs.

Siemens will also be responsible for the operating concept, organising the operating company, and training its personnel. Operational support will be provided for 18 months, along with maintenance of the system for 10 years.

The line has a capacity of 57,000 passengers per hour and direction. Trains will operate at two-minute headways with a commercial speed of 35km/h. Maximum speed of the trains is 80km/h.

Each metro train consists of two motor cars and a centre trailer car. The stainless-steel cars are based on Siemens' modular MO.MO metro concept. Siemens worked with Porsche on both the interior and exterior design.

The 65.1m-long and 3.12m-wide trains have 126 seats and standing room for 760 passengers at a density of 6/[m.sup.2]. The airconditioned trains are walk-through units.

The spaciously-designed air-conditioned underground stations are built on three and sometimes four levels. As a result, the 18 stations are equipped with a total of 250 escalators and lifts. Each station has three to four glass entrances. All entrances are 1m above the highest flood level ever recorded in the city. They also have portable barriers as a defense against inundation during the rainy season.

A digital train radio system transmits train number data; it also carries voice communication from the control centre to the drivers and passengers. An infrared transmission system passes on camera images of the platforms to the driver to allow him to operate the doors safely.

Points and signals are controlled via six Sicas interlockings, which are in turn controlled and operated via a Vicos OC 501 operations control system. As a fall-back measure, local operator consoles are provided for each interlocking.

There were special requirements for the automatic train control and braking precision. Platform screen doors called for a stopping accuracy of 99.9%. The LZB 700 M continuous automatic train control system controls the trains so that they stop directly in front of the platform doors which then open automatically. The platform doors prevent cold air escaping from the air-conditioned stations into the tunnels, and also keep passengers safely away from the tracks.