Beginning in the Hintok area, the railway was required to ascend into the mountains that formed the Thai-Burma border. For the engineers planning the route, this area was the most difficult for them to explore and plan a path. The Three-Tiered and Pack of Cards bridges were in fact switch-backs that provided a gentler slope for the trains to rise into the mountains.
This area – and its corresponding section on the Burmese section of the TBR – were also the most problematic for delivering necessary supplies. There were no roads and no permanent local inhabitants on either side of the border. This failure of logistics was one of the reasons the POWs working in these highlands suffered some of the greatest hardships. This included the main US group under the command of LTC Tharp on the Burmese section of the TBR.
One description of the TBR states that the grade of the rise into the highlands was still so steep — despite the use of the switch-backs — that trains had to stop to exchange locomotives to more powerful ones to drag the cargo through that area.
The Burmese section of the TBR actually extended about 40 Kms into Thailand. On 17 OCT 1943, the two sections of the TBR were joined at Konkoita. That area is now underwater in the reservoir behind the Vajiralongkorn Dam (aka Khao Laem Dam).
[Editor’s Note: this is also the same reservoir that flooded the town south of the Sangklaburi Mon village area that boasts the famous Mon Bridge.]
The highlands are officially known as the Tenasserim Hills:
There is a group of young Thais who have made a quest to explore and document the route of the TBR beyond Hellfire Pass. The jungle and ‘progress’ in the form of agricultural incursion are continuously degrading these remains. They have been working in the Thakanun area and more recently on the edge of the flooded area of the dam due to low water levels. It is amazing to me that these young men have taken such an interest in this period of Thai (world) history.
Some recently available photos from the SongKurai camp area. Some of the US POWs spent some time in this area post-completion before being consolidated to the Kanburi camp.
A personal story of a British POW at Kin SaiYok is found at: