The traffic systems in Thailand's capital can no longer keep pace with the growth of the metropolis. There is an urgent need for an extension to, and improvement in, local public transport services. At the end of the 20th century, the mechanized construction of underground traffic infrastructures is still at a very early stage of development in Asia and thus in Thailand too. The native geological conditions in Bangkok, the so-called "Bangkok Clay", are eminently suitable for the use of EPB Shields.
The EPB Shield S-142.1 and its sister machine, the S.142.2, were each equipped with 66 cutting knives and 8 overcutters per turn direction, as well as a center knife with four cutters. Equipment like that made it possible to achieve daily best performances of 38.4 meters and a weekly best performance of 200.4 meters. Densely-populated downtown Bangkok, bridge foundations and existing water tunnels were tunnelled under securely with only little overburden in some places. A further step in establishing mechanized tunnelling in Asia has thus been taken in Bangkok after the first projects in Taipeh and Singapore.