This is a highly underrated answer. Capitalism works on free markets, and the competition (Private vehicles, Busses on roads is not free due to government subsidy of the roadways). Politically, privatizing roadways will not fly.

" free to use" except for the fuel taxes we pay for maintaining roads (in the state I live in anyway). And yearly excise taxes on autothemselves, and tires too I think at time of purchase.

This is an oft overlooked force working against developing mass transit in the US. People just don't realize how expensive cars are. Partly because using a car is so engrained in people's lifestyle. The notion that most people in the US must own a multi-thousand dollar machine that requires extra cost of hundreds of dollars per month to insure, fuel, fix, as well as taxes to maintain the infrastructure it requires just to go to the grocery store or commute to work is insane when you stop to think about it.

@CrossRoads It's paid for by tax money, but people in densely populated areas are very much subsidising the ones in sparsely populated areas. The road taxes paid for by people in a 100-inhabitant village at the end of a 50-km side road do not remotely pay fully for the side road only they (and the mailman) use. There is a massive amount of solidarity built into the system as currently organised. And I think road taxes still don't pay for newly constructed roads.

Yes, towns and cities often take out multiyear bonds to pay for new roads, or get state and federal grants to pay for part of it. Guess how the bonds get pid back, and where the state/federal funds come from? Pretty sure it's taxes.

@gerrit But all of those small side roads would still be required to get people to a train station and you'll need parking there, too. Your comparison in your linked answer is ignoring that most U.S. cities have far more urban/suburban sprawl than typical European ones. Constructing train stations such that a large percentage of the population can walk to them is a perfectly reasonable thing to do in much of Western and Central Europe. Not so much in the vast majority of the U.S. or Canada outside of a few very dense city centers.

@reirab The fact that US cities have much more suburban sprawl than European ones is a consequence of (car) culture and public planning decisions, not of geography. Cities in countries like Sweden, Spain, Russia have the space to sprawl as much as US cities do, but for a variety of political and cultural (but not geographical) reasons, they do not. I've addressed that in a comment to the linked answer as well (and Nordic cities do sprawl more than cities in the rest of Europe, too).

@CrossRoads State/federal funds come from taxes, but not only road taxes. I pay income tax but not road tax; some of my income tax goes to roads. I'm entirely fine with that as I still very much depend on roads even when I don't drive on them myself, but it's something that deserves be recognised when considering how to fund for other types of infrastructure, such as railways.

@gerrit This answer is talking about Interstate highways vs. trains and the question is about a capitalist solution. I was just pointing out that those side roads are irrelevant to that, as you need them to get to either the Interstate or to a train station (and then you'll need them on the other side to get to your ultimate destination.)

@reirab That's an excellent point, but keep in mind that local roads being of the width and quality to support cars plays a role too. You can think of narrow medieval street or rugged wild-west trails that developed in a relatively organic way compared to the more centrally planned roads. With those types of roads, cars would be at a disadvantage (If walking/cycling took over in the local sense, that would be a huge advantage for passenger trains). In what seems to be a winner-takes-all transportation war both ends count.

The cost of fuel taxes is not nearly enough to cover all the externalities of cars i.e. CO2 emissions.

@CrossRoads, only about half the cost of the freeway system in the US comes from use taxes (ie. gas tax) -- the rest is general-fund. (My wife used to work for the federal highway administration -- during a government shutdown at the time they were one of the few offices that could still keep going, insofar as even with the general-fund cutoff they could continue work on projects from the other half of the inflow). And city streets are all municipally-funded -- as a cyclist, it used to bug the hell out of me when folks would falsely claim that I wasn't paying for the roads I used.

@CharlesDuffy A lot of highway funding in the U.S. comes from state taxes, though, especially state-level gas taxes. Federal funding is only a portion.

@wedstrom Yes, you're right. Roads systems laid out in the car era rather than hundreds of years ago is a big advantage to car traffic in North America vs. Europe, whereas the old, narrow streets do tend to discourage car travel in European cities.

@spacetyper While I don't object to this answer in the slightest, I think you're underestimating the value of not having to deal with transit schedules and locations or carrying all those groceries from the stop to your home and of having your own personal transportation readily available during long distance travel. I can go to the store once a week with a car; that probably isn't feasible with a bus. Maybe you don't have to have a car to use the grocery store, but it's sure a lot easier.

@gerrit Where I live roads are also paid for via property taxes, so I'm not sure you're claim that urban people are subsidizing rural roads holds up.

@jpmc26 I suspect very few people buy groceries by train. Rather by car, bus, bike, tram/streetcar, foot, home delivery. When I grew up we bought our weekly groceries by bike+trailer. I don't think grocery shopping is directly relevant for the question on intercity passenger rail.

@jpmc26 but that is also a result of cars being available. If most people wouldn't have a car, there probably would be a lot more smaller stores. No one would build massive grocery stores away from resident areas if not for people driving there by car. Since I last moved I have a supermarket 200m from my flat. I now drive a lot less to the big stores because the time spent in traffic jam and the price for gas isn't worth the small advantage of a bit more selection of products and a bit cheaper prices.

@Josef You still couldn't carry 6 or 7 bags of groceries to last an entire week. And people like living more spread out. I understand all this has costs, but that doesn't mean that it's "insane" to value the things cars enable us to do.

@Josef: But unless you are a confirmed urbanite, what you gain by having a supermarket 200 m from your flat, you lose by having to drive (or bike &c) many km to get outside the city for recreation.

@Josef - having lived in BOTH situations (NYC no car, suburbs with car), the latter is 10 times better, convenience wise and other considerations wise. Ever tried to travel anywhere on NYC subway at 1am on a Saturday (hint: half the trains are rerouted, delayed, and run once every 2 hours). Ever tried to get to work on time in morning rush on a green line subway (or blue) when you literally can't fit into the train without waiting for 3 more to pass?