This question is primarily about human performance. I do know about hypoxia, hence this question.
I'm busy designing a fictional region, currently in the 1930's. I have a railway line that climbs to 15,000ft (4670m) in order to traverse a mountain range. The line was build in the 1900's, with the climb being gradual at 1:100 gradient. The town on the Eastern side is at around 5,000ft. the town in the west is at about 7,000 ft. Distance by rail is about 800km, (about 10 to 14 hour journey) with about 20 to 40km spent at 15,000ft. Using real-world data, I only have a basic understanding of the human body, and would like to ask the following questions:
1.) With 1900's to 1930's attitudes, would it be "safe" / "wise" to send passenger trains over that pass?
2.) How would this altitude affect the drivers / firemen on the steam-engine's footplate?
3.) From a biological point of view, how do I make this journey more comfortable?
4.) Any other point which I might have missed.