The idea of building a permanent rail link between Burma through Thailand to China was first raised in the 1880's by the British colonial authorities in Burma. The route considered was between Phitsanoluk in northern Thailand (then the Kingdom of Siam) and Moulmein in Burma. However no investment was forthcoming and the idea was shelved.
As early as 1939, Japanese agents in Thailand were preparing the ground for the construction of the railway, once Japanese forces had taken control of South-East Asia. The railway was intended purely as a strategic military supply line for the movement of troops and equipment to the Burma Front, and ultimately for the invasion of India.
The Japanese had originally intended to use an Asian workforce to construct the railway, and indeed most of the railway labourers were from Burma, Java and Malaya - some 240,000 seems to be the most reliable estimate. However with the fall of Malaya, Singapore and Indonesia (then the Netherlands East Indies) in 1942, the occupying forces found themselves with a large number of prisoners of war, an event they had not planned for. What to do with these prisoners was a vexed question for the Japanese military administration for the first few weeks of their rule. It was then decided that these men - skilled, disciplined military personnel - were to be used to further the Japanese war effort.
Gradually the PoWs were grouped into 'Forces' and sent to work on various projects. Some went to Japan to work in mines and construction gangs, others to Saigon to do dock work, and still others to various parts of the newly created 'Greater East Asian Co-Prosperity Sphere'. The first group of PoWs who were ultimately to work on the railway, were those of 'A Force'. These 3,000 men were sent by ship to from Singapore to various places in Burma to work on airfield construction. Later in 1942 these isolated groups were concentrated at Thanbyuzayat to begin work on the Burma end of the railway. Construction began in June 1942, under the direction of the Imperial Japanese Army's 5th and 9th Railway Regiments. Gradually more forces were sent to Burma and Thailand; in total more than 60,000 prisoners of war were transported to the railway project during 1942-3. At the same time the 'Sweat Army' of labourers from Burma, ostensibly volunteers but many conscripted by the puppet Burmese government, toiled on the construction work. Conditions in Malaya after the capitulation of the Allies caused the collapse of agricultural production, forcing many undernourished Malayan plantation workers - mostly of Tamil extraction - to volunteer for work on the railway, the terms being "A dollar and a pound of rice per day". Many went purely for the rice.
The 415km line linking the Thai and Burmese railway systems was constructed simultaneously from both ends, Thanbyuzyat in Burma and Nong Pladuk in Thailand. The appalling conditions for those working on the railway are well documented elsewhere. The numbers of deaths speak for themselves. Disease (particularly dysentery, malaria, beriberi and savage cholera epidemics), starvation rations, overwork, poor or no accommodation or sanitation, and the individual brutality of Japanese and Korean engineers and guards, took their inevitable toll. Over 13,000 prisoners of war perished during the period between late 1942 and late 1945. The numbers of deaths of the Asian labourers is harder to calculate; around 100,000 seems to be the most reliable figure. During the infamous 'speedo' period, July to October 1943, the desperation of the Japanese engineers to finish construction on time, under severe pressure from their superiors in Tokyo, meant that many men were forced to do grinding manual labour around the clock - 62 hours work out of 72 hours appears to be the record. Rest days were rare. This, combined with the first outbreak of cholera, caused the death toll to reach its peak during this time.
The Thai and Burmese sections of line were joined near Konkoita in October 1943. Actual construction took a mere sixteen months - some would say a remarkable engineering feat. After the line was completed all of the PoWs were transferred from remote jungle camps to base camps and hospitals. Some, after recovery, formed new work parties destined for Japan, others returned to Singapore. A large number of PoWs remained in the Thailand base camps until the end of the war.
The majority of the Asian labourers remained in the jungle camps to operate the railway under Japanese command, and to undertake maintenance work on the line. From time to time PoW work parties were taken back onto the line to carry out maintenance work and cut wood fuel for the locomotives. This work became crucial to the Japanese; the situation on the Burma Front was becoming critical for them and their vulnerability in the waters of the South China Sea meant that the railway was a vital supply route that had, at all costs, to remain operational. An average of six trains per day operated for the life of the line, well below original Japanese expectations but still a major contribution to their strength on the Burmese Front.
The railway continued to operate, with some interruptions, until the final victory of Allied forces in August 1945. Slowly the prisoners of war and Asian labourers were rehabilitated and returned home. Some former PoW's remained in Thailand and Burma to recover their comrades from remote maintenance camps, and to work on grave recovery parties. The railway then fell into disuse through lack of maintenance, and in 1947 the line and rolling stock were sold to the Thai Government. The money being used for war reparations and to compensate those countries who lost rail stock to the Japanese. By 1957 the Thai government re-opened the section of line from Nong Pladuk to Nam Tok (known during wartime as Tha Sao), and this part of the railway still operates today. Much of the abandoned section has now been reclaimed by the jungle, but embankments, cuttings and bridge sites can still be found