Thai State Railways (State Railway of Thailand or SRT) still has at least three diesel locomotives built 71 years ago by long-defunct American manufacturer Davenport Locomotive Works in regular service. One, at Nakhon Lampang in the north of the country, is used regularly to switch cars into Chiang Mai-Bangkok services with passengers onboard.
The units were ordered from Westinghouse International Electric Co. as part of a major investment plan after World War II to rebuild the Thai rail network and repair wartime damage. As well as the Davenport-built locomotives to re-equip its fleet in the early 1950s, Thai Railways bought seven diesel-electrics built in Switzerland by Sulzer, which previously supplied six diesels in the 1930s. Some 100 new steam locos were supplied by Japanese builders.
Westinghouse supplied traction motors and other electrical equipment, subcontracting locomotive assembly to Davenport, which initially supplied 18 500-hp, four-axle, B-B diesels. The 53-ton, single-ended units, designed for freight service, were fitted with the Caterpillar D397 engine and traction motors rated at 460 hp.
Davenport eventually delivered 30 of the four-axle B-B units (numbered 511- 540, works numbers 2151-80 of 1952), plus 15 of a later 78-ton, six-axle, double-cab, 920-hp version designed for passenger service (numbered 571-585). These used two of the Caterpillar D397 engines. The larger locomotives are now retired, but some still exist, although in poor condition.
At least three of the four-axle locomotives remain in use. No. 540 is used at Nakhon Lampang, and sister unit 530 is in use at Uttaradit station, also in the country’s north. At least one other unit was seen recently at the SRT Makassan shops in Bangkok, and one or two more of the type may occasionally be used elsewhere.
The Davenport Locomotive Works, based in Davenport, Iowa, built steam locomotives beginning in 1902, and later produced diesel and gasoline-engined locomotives. Most Davenport diesels were built for North American customers, not for export. In 1955, Davenport was bought by Canadian builder Canadian Locomotive Co. (CLC), but production ended in 1956 and CLC itself was taken over by Fairbanks-Morse in 1965, not long before that company ceased locomotive manufacturing.
Later orders by SRT in the early 1960s also went to American manufacturers, with GE supplying the UM12C “Shovelnose” four-axle design. Many of these many remain in service in Thailand, having been overhauled in recent years.