Reducing the difficulty of a railroad to regulatory approval (what the comment you replied to does) is really oversimplifying it. The main barrier to building

Reducing the difficulty of a railroad to regulatory approval (what the comment you replied to does) is really oversimplifying it. The main barrier to building modern rail (i.e. high speed rail) is property owners. Nobody wants to be forced to sell off part of their property to the state to add noise pollution to their property. So everyone fights it tooth and nail. That's of course a problem and it happens with roads as well but it's standard practice to just eminent domain property for roads if people won't sell. The state will not do this for railroads though. So a railroad project may end up blocked for 20 years because they don't own a 1 mile stretch of land 20 feet wide but with a new highway extension they'll just eminent domain your half your property and bulldose your home after 5 years of negotiating to add a few lanes to an existing road. This is not to say that eminent domain is a good thing but rather that it's a lot more naunced than "regulators won't rubberstamp the project"