It would cost hundreds of billions of dollars to string up the overhead wire by themselves, and that's using the lowest cost electrification jobs done world-wid

It would cost hundreds of billions of dollars to string up the overhead wire by themselves, and that's using the lowest cost electrification jobs done world-wide. It would cost hundreds of billions more to actually clear bridges and tunnels for the extra height needed for catenary. Then you'd have to actually buy all of the locomotives (not even going to speculate there). And then there's probably significant extra cost in building out transmission infrastructure to the railroad tracks--I'd guess there's large slices of the West where there's nothing around nearby you could hook traction substations up to. All-in-all, you're talking about a trillion-dollar investment to do so. At the same time... the performance benefits really aren't worth it for freight trains. Remember that diesel locomotives are already an electric drivetrain--the diesel is merely fueling a generator that's sitting on board to power the drivetrain. The big savings with electrification come with weight reduction--and with freight, the weight of the locomotive is a small component of that weight--or using EMUs that let you have every wheel being powered (and with freight cars, that's again never going to happen).