[ExBritNStuff]

Maybe over the long term, but I wouldn't say that for certain given the insane costs of building infrastructure in that kind of environment. However, I can say that it would totally defeat the purpose of trying to keep things secret. Any tracks would be visible in satellite images and show exactly where the trains go.

[mrguyorama]

planes are not hard to track

[bunderbunder]

They were presumably a fair bit harder to track in 1972.