As has been pointed out, this is a highly imaginative account of the building of the Canadian Pacific. Perhaps the Scott character is based on Major Albert Bowman Rogers who, Wikipedia tells us, was tasked with finding a route through the Selkirk Mountains. The CPR promised him a cheque for $5,000 and that the pass would be named in his honour. Rogers became obsessed with finding such a pass and discovered it in April 1881.

I saw it some years ago on British TV and have just watched it again courtesy of a slightly fuzzy copy on YouTube. Just about the only scenes I recalled were Scott's miraculous escape from the dynamite explosion (not completely impossible, I understand), the bandage on Scott's head that shifted in the same scene, and Dynamite Dawson's escape from the Indians.

The blood transfusion scene (in a moving train that was remarkably stable) was perhaps a bit ahead of its time. By the late 19th century, blood transfusion was still regarded as a risky and dubious procedure, and was largely shunned by the medical establishment.

Scott, in his early fifties, again has two far young women vying for his affections, but he was still a good-looking guy.

I enjoy these American "building-a-railroad" films, and this was good entertainment.