The real commander of the 2nd battalion Argyll and Sutherland Highlanders, Lieutenant Colonel Ian Stewart, was not killed in a POW camp. He, and some others, managed to escape to India.
Lt. Jim Reardon or "Yanker" as he is referred to in the film, would not have been in a wheelchair in the camp. The truth is, his back was too severely broken for him to be transported anywhere. He spent the rest of the time in camp bed-ridden. He appeared in a wheelchair in the film simply for camera flow.
The camp in the film seems to hold about 200 prisoners. The real camps on the railway held 1000s.
The Japanese vehicles are shown as left-hand drive vehicles. Japan has always driven on the left and, unless they acquired captured US (LHD) vehicles, they would have driven right-hand drive vehicles. During the Second World War both Burma and Thailand drove on the left. Thailand still does but Burma changed in 1970.
At the end when the veterans are marching, a caption says they are from the 93rd Division of the Argyll and Sutherland Highlanders. It should say the 93rd Regiment.
When the colonel has just been shot, Keifer Sutherland talks about not being kamikazes if they want to escape the camp. At that time in the war, the term kamikaze would not have been known to Allied soldiers.
The Japanese commander's vehicle is a Willys M38 Jeep, while it's possible that the Japanese used captured vehicles, this type was first produced in 1950.
When Yank tries to persuade Ernie they should escape the camp, he tells him he is not kamikaze (suicidal). That moment in the movie is set in the beginning of 1942, but the first kamikaze (suicidal pilots) actually appear in 1944.
During the funeral scene for the Colonel, a piper begins to play a rendition of "Amazing Grace". While this hymn was published in 1779, it was not performed on bagpipes until 1972 by the Royal Scots Dragoon Guards.