The section of the TBR just beyond Hellfire Pass is generally referred to as the Hintok or Kanyu area (there are many varied spellings; ). It is notable for a variety of reasons. From an engineering perspective, this was a critical area where the railway began its rise into what I am calling the highlands of the Thai section of the line. From Nong Pladuk to Khao Poon (Chung Kai) the line was essentially at sea level. The two small cuttings at Khao Poon were needed to avoid a ‘high spot’ (I hesitate to call it a mountain; more like a large hill). At Wang Po the line runs about 30 meters above the river but the approach was quite gradual and required no significant alteration of an essentially straight line. Beginning at Hellfire Pass, the rail line is approaching the mountains that straddle the Thai-Burma border.
Three Pagodas Pass is about 300 meters of elevation. To get the trains that high was an engineering problem. The locomotives of the era could not pull cargo up a steep gradient. So the long curved section depicted in the map below was needed to create a gradual gradient. Even with this it became necessary to change to a more powerful locomotive to get the trains into the highlands. Once there, a lesser locomotive could be used to cross the border and descend towards Thanbyuzayat.
 HellFire Pass is also known as the Kanyo Cut.
A small group of US POWs were attached to H-Force and found themselves working the TBR in this area. They were only there for about six months before being returned to Singapore. One issue that plagued H-Force and F-Force is that they were never technically added to the Thai-based IJA administration; meaning that all their support and logistics came via Singapore. This contingent of 23 US personnel included 7 Merchant Marines from the SS Sawolka as well as others who had initially been left in hospital in Singapore as the various US groups passed through there. The US personnel were said to have participated in the building of the Three-Tiered Bridge.
This area was also hit by the largest cholera outbreak on the Thai-side of the TBR. Fortunately, no US personnel were felled by that dreaded disease.
This is also the area where the famed Australian doctor and later statesman, E.E. “Weary” Dunlop was the commander of a POW camp and made his connection with Khun BoonPong.
US POWs at Hintok
Beyond to the famous bridge, there are two somewhat less recognized portions of the Death Railway: The WangPo viaduct and Hellfire Pass. The former is still in use by the train that departs the River Kwai Station for NamTok. The latter is a bit farther west (about 80 Km from the Bridge) and has a Memorial Museum operated by the Australian gov’t. The Pass itself is no longer on the active rail line. It is possible to do a multi-hour trek along the former path of the railway. (see the URL below for a tour)
I am only aware of one survivor account that addresses the plight of the Merchant Mariners: DEATH’S RAILWAY by Gerald Reminick. He relates that the US POWs worked on what became termed the “Pack of Cards” bridge/ trestle. So named because it collapsed a number of times during its construction. It was dismantled after the war and at present there are no known photos of that section of the railway.
Also see Section 3.3 for a brief discussion of the Merchant Mariner’s role.
See Section 20 for the story of the Asian forced laborers (aka romusha).
The romusha work on the Thai sector of the TBR began in earnest at Hellfire Pass and The Hintok area. While technically the Thais who built the initial 50+ kilometers of the TBR were romusha, their time (Jun-Dec 42) pre-dated the horrendous conditions under which the romusha worked farther along. The majority of the romusha who worked the TBR in Thailand were Malay-Tamils.
Some of the highest mortality rates were among the romusha who worked beyond Hintok in the highlands in the Thai sector. This was largely due to outbreaks of cholera in those camps.
Also in the Hintok area was a camp known as the Malay Hamlet. It was assigned to members of the H Force who were soon re-assigned the duty of assisting D Force in building HellFire Pass. The AUS POWs at the Hamlet camp were struck hard by cholera. That camp was as far as the cholera epidemic spread to the east.