The actual building of the TBR was almost purely manual labor. The two exceptions were the use of elephants to move logs in the jungle and the occasional availability of air hammers in the cuttings.
There is a (possibly apocryphal) story of a camp guard handing over a camera to the Australian Team searching for POW remains. That is possibly the source of some of the above photos. Otherwise, they would have to be re-enactments of POWs working.
Kwae Noi river was a major route of transportation of supplies. Unfortunately, never enough to met the demand.
As translated from the original t=Thai as posted by Thansawath Saranyathadawong:
Japanese military transport convoy in Kwai Noi River During the construction of the Death Railway, Transportation of woodworking tools, work equipment, food and items for the livelihoods of prisoners of war.
Asian commissioners Japanese soldiers in remote areas are very important, and the most convenient route to transport items is by boat up the River Kwai Noi, since traveling on land roads is quite difficult, especially during the rainy season. Land routes become muddy, making traveling by vehicle almost impossible. Therefore, river transport is considered important, but boat transport during the rainy season itself is limited. Navigation must be paused due to the danger of logs, bamboo formations or items floating in the water during high waters. If sailing, it could damage a boat or could even be sunk by something floating along the river. The rushing currents during heavy rains are also barriers to navigation in the River Kwai Noi. The main cause of the famine of prisoners of war and Asian commissioners is these transportation problems.
P.S. Years ago, the ship was discovered. T.Praangasi
It is estimated that the ship was used during World War II.
It seems that in their haste to complete the Railway the existing rails were used almost exclusively to move the iron rails and wooden ties (aka sleepers). IOW no food medication or other items in desperately short supply were moved by rail to the camps deeper in the jungles. Rarely, were any POWs moved via the railway until after completion and the mass consolidation to KAN was taking place. Even the sickest of men were most often moved by barge down the Kwae Noi, likely to the ChungKai hospital camp.
Here, too, the POWs made drawings of their efforts:
Most of the above photos were extracted from the on-line archives of the Australian War Museum:
https://www.awm.gov.au/advanced-search
The following set of photos seems rather odd in that they depict IJA soldiers (engineers?) working alongside Allied POWs. They have been posted to a Thai language site on FACEBOOK but without attribution as to exact place or time. IMHO, these appear to be AWM photos but this has yet to be verified. The general state of health of the Allied soldiers and their clothing suggests to me that these are post-war staged photos, but the reasoning is unknown.
The last photo above is labelled as: สะพานข้ามแม่น้ำ ข้ามห้วยและหุบเหวใหญ่น้อย or Kaam Huay Lae Hup Heaw Yai Nioi (?) If anyone can assist in putting a time or place to these or verify that they are from the AWM archives, please leave a COMMENT.