Especially the interurban lines that built every American megacity. Small single driver electric trains (basically trolleys but designed to go faster than streetcars and ran on dedicated right of way outside of the city) they were a really efficient method of transporting people into cities, many allowed for flag stops (where a passenger would flag down the car anywhere along the tracks to stop so they could get on) and would run between cities, feeding from smaller towns into larger ones or just running between nearby cities.

Unfortunately passenger railroad service has always been unprofitable. Until the 1960s most passenger services were largely paid for by lucrative mail contracts and would haul Railroad Post Offices, which were delicated cars with tiny postal sorting facilities in them that post workers would sort the incoming and outgoing mail on and pickup and drop off big bundles of mail at every stop and often even without stopping. Most interurban and trolley lines were largely real estate schemes where they'd buy comparatively cheap farm land, build a rail stop and possibly a few homes and businesses near the stop to sell for a tidy profit, then sell the rest of the land plot by plot now that the rail connection and other nearby homes and businesses made it far more valuable. This was even the tactic when building the transcontinental railroad, where the railroad companies built entire cities along the way.

So simply put, railroad construction and operation is prohibitively expensive. On the other hand, if the US Federal Government matched their spending on highways for railroad expansion the cost of rail transport would probably blow the cost of driving or hiring a truck out of the water entirely