content: In Musk's original white paper he points out that one of the major expenses for rail lines is land. You have to buy a lot of it and you usually have to buy pretty specific parcels to maintain grade and avoid sharp curves. One of his proposed advantages with HyperLoop is that it is elevated and the pylons can be placed in the middle of interstates, like I-5. So you have a significant savings just in land. You also avoid the need for rail crossings of any kind because the entire thing is already meant to be elevated out of the way.