A railway route between Burma and Thailand, crossing Three Pagodas Pass and following the valley of the Kwhae Noi river in Thailand, had been surveyed by the British government of Burma as early as 1885, but the proposed course of the line – through hilly jungle terrain divided by many rivers – was considered too difficult to undertake.
In early 1942, Japanese forces invaded Burma and seized control of the colony from the United Kingdom. To supply their forces in Burma, the Japanese depended upon the sea, bringing supplies and troops to Burma around the Malay peninsula and through theStrait of Malacca and the Andaman Sea. This route was vulnerable to attack by Allied submarines, especially after the Japanese defeat at the Battle of Midway in June 1942. To avoid a hazardous 2,000 miles (3,200 km) sea journey around the Malay peninsula, a railway from Bangkok, Thailand to Rangoon, Burma seemed a feasible alternative. The Japanese began this project in June 1942.
Abandoned section of Burma Railway in Thanbyuzayat, Burma
The project aimed to connect Ban Pong in Thailand with Thanbyuzayat in Burma, linking up with existing railways at both places. Its route was through Three Pagodas Pass on the border of Thailand and Burma. 69 miles (111 km) of the railway were in Burma and the remaining 189 miles (304 km) were in Thailand. The movement of POWs northward from Changi prison in Singapore and other prison camps in Southeast Asia began in May 1942. After preliminary work of airfields and infrastructure, construction of the railway began in Burma on 15 September 1942 and in Thailand in November. The projected completion date was December 1943. Most of the construction materials, including tracks and sleepers, were brought from dismantled branches of Malaya's Federated Malay States Railway network and the East Indies' various rail networks.
The railway was completed ahead of schedule. On 17 October 1943, construction gangs originating in Burma and working south met up with construction gangs originating in Thailand and working north. The two sections of the line met at kilometre 263, about 18 km (11 mi) south of the Three Pagodas Pass at Konkuita (Kaeng Khoi Tha, Sangkhla Buri district, Kanchanaburi Province).
The Burma railway was an impressive accomplishment. As an American engineer said after viewing the project, "What makes this an engineering feat is the totality of it, the accumulation of factors. The total length of miles, the total number of bridges — over 600, including six to eight long-span bridges — the total number of people who were involved (one-quarter of a million), the very short time in which they managed to accomplish it, and the extreme conditions they accomplished it under. They had very little transportation to get stuff to and from the workers, they had almost no medication, they couldn’t get food let alone materials, they had no tools to work with except for basic things like spades and hammers, and they worked in extremely difficult conditions — in the jungle with its heat and humidity. All of that makes this railway an extraordinary accomplishment."
The total freight carried during the war was 500,000 tonnes and two Japanese Army divisions.