So here’s the question they ask us Americans, why are we still using Diesel Locomotives while other countries are mostly Electric Locomotives?
To make a long story short: because American railroad operators are allergic to intensive capital investments. They could have easily done so in the 1890’s but they all flirted with the very edge of the idea waiting for an excuse to do so: which was someone to go first. But because no one went in first no one did.
Intercity and light rail railroads did go into electricity hella hard. But because the balkanized rail network of America wasn’t all that comprehensive (and the carriers all didn’t care about passenger rail at all) they were left vulnerable to being torn out for car infrastructure. There are still some surprising bastions of light urban rail here and there outside or some major cities (Boston, Chicago, NYC, etc) but mostly in like, Ohio and Minneapolis.
The idea was revived again during the short Conrail era but because Conrail was composed of dyed in the wool Penn Central freaks the government was obliged to step down because they refused. In fact: the government proposal to consolidate and trim the rail network was rejected by them because they wanted it trimmed down more.
And that’s how we got Amtrak as it is today.
The good thing about diesel locomotives is that overall they’re still more effective and green than trucking and road traffic. In theory, if certain rail theory was done right than they’d still be doing as clean a job as any non-French trains. But that requires that all the class 1’s actually do intensive capital investments. And they hate that.