Nation-wide railroad network: To incentivize its' construction, the US government gave away huge land grants (much of it land of various Indian tribes) to corporations. The US maintains a federal bureaucracy to support rail transportation.
The rail companies kind of cheated this idea, too. If you've ever explored the American West, you probably came across various and sundry ancient rail sections inexplicably placed haphazardly all over the place. These rails were never connected to the rail network system, and were certianly ever useful to anyone in any meaningful way. Want to know why? Railroad land grants. You see, the rail companies initially would got an odd section of land on each side of the track for every mile of track built, resulting in a kind of checkerboard pattern if you looked at it on the survey.
The idea being the rail companies would subsidize track building through selling real estate near the track. Seemed sensible enough, right? What happened was this: in any place that was reasonably habitable (water, fertile land, the usual things that make life nice), the rail companies would build track alongside the main track such that the checkerboard was filled in, giving them 20 miles on either side of the main rail. They received the deed to the land, and often came along and recuperated their materials to use on yet another section of track, repeating the process. This allowed them to quickly and cheaply become the legal owners of huge swaths of land.
Eventually, they'd sell the granted land, making a tidy profit. They'd usually retain the mineral rights, however. Interestingly, the several rail companies to this day retain more mineral-acres than anyone, and still make insane amounts of cash on mineral leases to this day.