If you want an example of high speed rail right of ways, look at surface right of ways.

Existing and new double track commuter rail lines are typically 12′-14′ in track centers, and another 10′ on each side to the edge of the ballast. If a drainage ditch or major fill is provided, you could add another 10 ft. to each side. High speed rail lines are 16′ track centers, and 25′ track centers where possible. You can add more tracks at the track center dimension without affecting anything else. All of these iterrations fit into the typical 66 ft.-100 ft. wide railroad property right of way. Most of Amtrak’s Northeast Corridor is 4 tracks slid between catenary poles set 62 ft. apart, with about 19′ ft. on each side of additional property. Amtrak permits commuter trains to be scheduled to a density of 20 trains per hour, and Amtrak’s own trains at a density of 12 trains per hour. The commuter trains are 12 cars holding 120+ people each – 1500 per train. The Amtrak trains are 8 cars or more holding 70 people each. The platforms are laid out to permit use of up to 14 car Amtrak trains without major issue (1200 ft.). If trains are stopping, about 15 trains per hour can run on a line, so 22,500 commuters and 10,000 on Amtrak = 32,500 in one direction, or 65,000 per hour.

Obviously every train is not that long, and those densities are not actually approached in real service for any lengthy period of time. Of course, the same can be said for for highways filled with single occupancy vehicles for a few hours per day.

As to whether a rail line can carry a freeway’s worth of traffic, the typical 4-8 lane freeway in this country carries 50,000-200,000 cars per day. There are dozens of urban rail lines with that kind of ridership, including nearly every subway line.

http://youtu.be/7HgQ-jENojQ

A think it’s a pretty nifty idea.
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