Railroads in America ended WWII flush with cash from all the wartime traffic and would soon embrace lots of new technologies, diesel locomotives instead of steam, radio communications instead of the telegraph, computerized centralized dispatching and control instead of a signal box every few miles with a man in it to pull levers, welded continuous rail instead of old bolted joint-rail for smoother rides. Etc.
And yet, only a decade later, a lot of railroads were failing, and later still, in the 60's, a lot had actually failed, with the absolute nadir coming in the early 70's when Congress rescued 15 bankrupt railroads by creating Conrail. (adjusted for inflation, the bankruptcy of the Penn Central Railroad in 72' was the costliest one-time loss of capital in American business history until Enron)
What happened?
They got out-competed by trucks, planes and personal cars, basically.
And passenger rail service was something all the major railroads would just give up on circa 1965 - 1974 as they looked for things to slash off the budget to try and stay alive.
So why was passenger service losing them money? Or rather, why couldn't they compete with the alternatives?
- Speed - Planes can always beat trains, so city-to-city and coast to coast travel in this country is ruled by commercial air, and has been since about the mid 50's when the nessecarry tech and infrastructure to do cross country flights became robust and mature enough that it was safe and routine. Nobody wanted to take a 9 hour train ride if the alternative for just as much (or maybe a little more) in fare would do the whole thing in 2 hours. Ah, but what about HSR, TowinKarz? Trains in Europe compete on city to city routes with airlines, why can't we? Because our railroad right-of-ways were laid out in the 19th Century, when "high speed" was 90 mph. The curves are too sharp and grades too steep to run at HSR speeds. And since everything that came AFTER railroads filled in all the gaps, as cities grew up around the tracks, and roads tunneled under or bridged over them, the routes are effectively hemmed in and cannot be upgraded to HSR standards without obliterating large parts of entire towns or having to rebuild hundreds of miles of bridges , cuts, fills, tunnels, etc. This is simply an impossible cost to pay, to say nothing of the suicidal political cost of telling your constituents that their neighborhood has to go for a train they'll never use. Europe doesn't have this problem because their rail systems were reduced to ash and twisted metal during WWII and had the luxury of rebuilding them with HSR in mind. This is also the reason they nationalized the rail systems and cut out the need to placate shareholders and stubborn CEOs when they rebuilt everything. Nationalization never happened in the US. Speaking of which.
- Private Company, Bro! - Amtrak actually owns very very little "trak" - see that blue line on the 2006 map running from about New York to Baltimore? That's the northeast corridor, the only part of the whole passenger system that Amtrak actually owns and can call the shots on. The rest of those white lines? They only get to use them by buying trackage rights (permission to use your stuff on our rails) from a freight railroad that owns it. (Norfolk Southern, BNSF, Union Pacific, etc) - The Government doesn't have the legal authority to force these companies to take passenger traffic, much less give it priority. They can tell you to go screw and that's it, no court in the land can make them reconsider (except in case of WWIII) Even if NS says "sure" - you don't get to pick the timetable - you'll be fit in where you can fit in and if that means waiting behind a load of cement, or lumber or shipping containers or burning hazardous chemicals? Then yer' waiting. Don't' like it? Just go build your own railroad, dude! lamao! Needless to say, freight lines are NOT high-speed and have no real incentive to be (under Federal law max speed for a freight train is like 70, go any faster and you get a fine) so even "high speed" Amtrak trains can't use all of their 125 mph potential, assuming they even could without derailing on a 40 degree turn.
- Loss of Expedited Freight - A lot of passenger routes carried more than just passengers. Particularly, what we'd nowadays call "LTL" (Less than Truckload) freight. Used to be, back in the day, that express packages and mail were carried aboard passenger trains, The innovation of freeways and ability for FedEx or UPS to drive right up to your doorstep put that railroad less-than-load freight/merchandise market out of business, and OTR trucks took over most of the city-to-city mail. Again, if they could drive direct from post office to post office and cut out the train as an unneeded middleman with loading and unloading times on both ends now being skippable, why not? Lots of passenger trains that operated by absorbing the loss on ticket sales by carrying contracted mail were discontinued in the early 70's as trucks stole that market. Some old eastern cities still have humongous legacy post office or railway express agency buildings downtown, usually across the street from where the railroad station is/was, that used to be the gathering point for all this traffic. If they still exist, they're hipster bughives.
- Labor costs - to take a coast-to-coast train ride, from LA to NYC, let's say, will take several days. Train engineers are regulated just like truck drivers and airline pilots- there are max hours they can be driving/flying before they have to take a mandated break. That train will need at least two, possibly three full crews who can work in rotation to get that train across the country, meeting up at designated places/stations to swap out. Whereas Delta can do that same trip with the same crew the whole way and probably hit 2 or 3 more cities too.
It will cost more in labor, at union rates, to cover "X" distance by train than by plane, always. Unless the North American continent were to suddenly shrink by 2/3rds, planes will rule long-distance travel. Well, what about short then? You may ask.....
- Unprofitable local services - If you think the coast-to-coast issue is bad? Going from suburb to city is even worse. One of the very first casualties of the big decline in railroads post WWII were the loss of so called "milk run" railroads, small, regional or local lines that only connected a mid size city to it's ring of supporting farm and outlier communities. They got the name because they were how farmers got their milk and produce to market in an era before good roads or heavy trucking. Once those things did come to pass after WWII? That was it for them. Trucks took 100% of that traffic and the meager remaining commuter service wasn't enough to live off of, especially as car ownership really took off. (same thing doomed street cars, another thing a lot of mid sized US cities used to have) And as these lines died, they were usually ripped out for scrap value and their right of ways subsumed into new freeway alignments, suburbs or strip malls. We can't even "just fix them up" and start using them again because they're GONE. My local university used to have a train station right on campus for out-of-town and out-of-state students to arrive on. It also brought in the coal for the campus steam plant. My Dad rode it in when he was a student in the late 50s, by the 60's? It was not just abandoned, but gone to make room for a new research lab as everyone took a bus or car to get there and the coal was now coming by truck. The old train track grade is now mostly a bike path and several new downtown buildings ate up large pieces of it to make parking lots, also, a bridge over the main thoroughfare was removed years ago as an overhead clearance hazard, the train is gone and never coming back, the costs to integrate it back into the urban plan are just insurmountable. And so it goes in hundreds of other cities and towns like mine. Commuter rail is a literal impossible dream in most of these places as there's no way to put it back or add it to the existing areas, and the economics of our car-centric life (whether you agree with it or not) means it likely will be just as big a money-loser today as it was in the 50's, there's a reason they left it all to rot - it didn't make money.
Hope that helps put some perspective on why we just can't do as Europe does and fall in love with trains.
We were in love with them, then newer, cheaper, faster things made us fall out of love.