|Exactly what a space train would look like.|
I still don't understand why people are obsessed with space trains. It's all well and good until some aliens or rebel space forces decides to come after you!
Anyway, the good folks at io9 have an interesting article up about the feasibility of such a project.
Also, way to go io9 for identifying what happens inside my brain and then creating a site that feeds into it. You have a perfect marketing/editorial team.
Here's an even more detailed article about it at Gizmag, with pictures.