It would have been a lot cheaper if the military didn't order the Tonopah & Tidewater Railway to be dismantled for its precious steel. That would be like half the line.
It had already ceased operation before the start of the war (in the US), and would have been taken up for scrap sooner or later anyway. Even without World War II, there is exactly zero chance that the railroad would have survived long enough to be useful again. Unused rail lines don't sit for 50 years without being scrapped. (At least, they didn't in those days. Tennessee Pass seems to be headed toward becoming the exception that proves the rule.)
https://en.m.wikipedia.org/wiki/Tonopah_and_Tidewater_Railro...