How do private companies arrange infrastructure-sized projects? Oil companies seem to have substantial arrangements like these. Railroads maintain a lot of in

How do private companies arrange infrastructure-sized projects? Oil companies seem to have substantial arrangements like these. Railroads maintain a lot of infrastructure privately. I'm guessing these companies don't get gouged like the government, but they really have all the same issues, like internal corruption, the bid process, change orders, competing interests in the company, etc.