The Dutch had investigated the possibility of a railway to connect the East and West coasts of Sumatra in order to allow access to coal fields which could be found inland. This railway was to join the existing on which ran from Padang to Moeara.
Swamps and the dense jungle would have to be crossed and cut through, and bridges would have to be built across rivers which were prone to flooding during the monsoon season. This all, when coupled with the many prevalent diseases, such as malaria, and the animals (tigers and bears) made the idea of a railway "too hard", and requiring too many resources.
When the Japanese occupied Indonesia, the original plans that had been put in place for this railway came to light, and rather than re-shelve these plans it was decided that this railway was indeed feasible - after all, they had the slave labour that would be necessary to carry out its construction. This railway would also allow the Japanese easily move troops between coasts, and would allow them to avoid travelling through areas which were heavily patrolled by allied warships in order to reach the Melacca Straits.
Originally local "volunteers" (Romushas) were used, under the false premises of good payment, food and living conditions being provided in return for the work carried out. When these volunteer numbers declined, due to the abismal conditions that the Romushas had to work in, forced labour was introduced, and in 1944 the decision was made to use POW's to complete this railway. The first prisoners arrived during May 1944, and would remain there until the late in the following year, after the Japanese capitulation on 15 August 1945.