The days of steam locomotives puffing along a track and pulling carriages full of passengers and goods are long gone.
Many of the "iron horses" in the world completed their final journey a long time ago. Only five of them remain in Thailand, appearing in public only on special occasions as a vivid reminder of a bygone era.
Steam-driven locomotives are now replaced by modern and faster diesel and electric trains.
Still, Thailand's railway transport, which has more than 120 years of history, appears to be trundling along at a snail's pace with the future lying far ahead.
A steam locomotive is fuelled by fire-burning coke, wood or oil heating water in a boiler to generate steam. The steam power drives the engine and the wheels, with tenders, or tanks on wheels carrying coal and water supplies pulled behind.
Steam locomotives were originally developed in Great Britain in the early 19th century with George Stephenson, an English civil engineer, inventing the famous locomotive "Rocket" in 1829.
In the Kingdom of Siam, King Rama V, who was considered the father of Thai trains, approved the establishment of the Department of Railway for the first time in October 1890.
The country's first railway route linking Bangkok and Samut Prakan was operated by a private, foreign-owned company which won a concession to operate rail service.
Steam locomotives continued to gain in popularity and were in high demand by many countries during World War II.
In 1928, the first diesel locomotive was introduced to Thailand, gradually superseding the steam-powered locomotives which required complicated and labour-intensive procedures to keep them running.
The locomotive driven by a diesel engine is easier to operate with low maintenance costs.
In Thailand, the role of steam locomotives carrying passengers and goods was gradually relegated from the long-haul train service to short-haul train or community train, before the State Railway of Thailand brought down the final curtain on the steam locomotive rail service in 1977.
The five remaining steam locomotives in Thailand are kept at the Thon Buri Locomotive Depot in Bangkok Noi district. They are modified to be powered by new types of fuel instead of coal or wood.
On special occasions, they are brought out to transport people on special trips on routes in Kanchanaburi and Ayutthaya.
The steam-powered locomotives are usually put on public display four times a year — on the founding day of Thai railways on March 26; Her Majesty the Queen's birthday on Aug 12; the anniversary of the passing of King Rama V on Oct 23; and His Majesty the King's birthday on Dec 5.
The five steam locomotives comprise two C56 class locomotives, Nos 713 and 715, built in Japan and brought to Thailand in 1946.
The others are two Pacific type locomotives, Nos 824 and 850, built by the Japan Association of Railway Industry and introduced to Thailand between 1949-1951; and a Mikado steam locomotive No. 953 built by the Japan Association of Railway Industry and introduced to Thailand between 1949-1951.
In their heyday, steam locomotives were seen as a brilliant invention dominating railway transport.
They were convenient, fast and safe, with constant improvements made to enhance efficiency.
Early steam locomotives travelled at a speed of between 50-60 km an hour but the pace of Thailand's present-day trains is still achingly slow at only 40-50km/h.
