The Japanese will carry out [their] schedule and do not mind if the line is dotted with crosses.
[Brigadier A. Varley, A Force, 24 May 1943. quoted in Lionel Wigmore, The Japanese Thrust, Canberra, Australian War Memorial, 1957, 554]
The 415 kilometres of the Burma-Thailand railway were completed in the remarkably short period of twelve months. Started in October 1942 the two sections of the line met at Konkoita, in upper Thailand, in October 1943.
The Japanese desire for speed was reflected in every aspect of the railway's construction. The significant engineering challenges, the problems of logistics, the inhospitable climate, the remoteness of many work sites and the lack of modern equipment ensured that the Burma-Thailand railway was completed at the cost of perhaps 102,000 lives.
Rather than adopting the more traditional approach to railway construction of advancing the railway from each end the Japanese constructed the railway simultaneously at many points along its entire length, with only the track-laying progressing from each end.
The construction of the railway was under the command of the Southern Army Railway Corps. The 5th Railway Regiment was responsible for the Burma section of the line, while the 9th Railway Regiment supervised the construction of the Thailand section. Around 12 000 Japanese were employed on the Burma-Thailand railway, mostly as engineers and guards. The guards included some 800 Koreans conscripted into the Japanese army.
The workforce was organised into groups of between 2000 and 12 000 men. Two groups operated in Burma (now Myanmar) while four were in Thailand. Another 10 000 prisoners of war were administered directly by Japanese forces in Malaya (now Malaysia).
Before leaving Singapore the prisoners were formed into 'forces', named variously after a letter of the alphabet or the name of their commanding officer. Dunlop Force, D Force, F Force and H Force worked in Thailand, while A Force and others worked in Burma. Most forces were multinational though they were broken down into battalions, which were usually organised and led along national lines. Once on location the forces were broken apart and the men allocated to work groups as required by the railway's construction schedule.
There was little consistency in the forces' structure and size. They depended on the scale and difficulty of the task at hand. Conditions also varied greatly between working parties as units within the Japanese Army often operated with little day-to-day coordination with each other.
The need for large numbers of labourers was dictated by the relative lack of modern construction equipment. Cuttings like Hellfire Pass (Konyu Cutting) were often excavated by manual drilling in the rock of holes for explosives. Pile drivers used in bridge construction were hauled up by teams of men as in classical times.
As far as possible, materials were sourced from the surrounding countryside. Little shipping space could be spared for transporting construction materials from outside though some rolling stock was brought from dismantled railways in Burma, Malaya and Java. The wood for bridges was extracted from the jungle, cut and hauled to the construction site. Embankments were constructed from stone and earth laboriously gathered and carried by prisoners, often up steep hills.
On the Thai side of the railway the Kwae Noi was an important supply line for the railway. The river was navigable to Tha Kanun during the dry season and to Konkoita during the wet. However the logistical system broke down as the workforce became more remote from the base of supplies and the monsoon in mid-1943 made the the single road unpassable and the river torrential.
While working for long hours on the railway construction the prisoners and rǒmusha had also to work on other tasks: building their accommodation and camps, creating sanitary systems and hospitals, and preparing food.
So challenging was life on the railway that one prisoner, John Coast said of the 'Pack of Cards Bridge', a particularly troublesome and difficult project a short distance beyond Hellfire Pass (Konyu Cutting):
No other nation in the world in 1943 would have bashed and bullied, and sweated and slaved prisoners to such fantastic lengths for such an object.
[Quoted in Lionel Wigmore, The Japanese Thrust, Canberra, Australian War Memorial, 1957, 569]