I agree our planning should not reflexively start with the same assumptions and expectations that are believed to "work" on a continent instead of an island.  

Whether the rail guideway is converted to a bikeway, a bus only road, an HOV or emergency road--or some combination thereof--I have heard of covered bikeways elsewhere (in Europe, I believe)--with solar panels on the roof.  Pilot projects in the UK and Australia are also testing road surfaces that generate electricity from the kinetic energy created by road users. 

Noa Lincoln's comment also made me think again of part of one of my own earlier comments today that may go unnoticed because this comment system does not allow internet links to display visually.  But I will re-post it here again because it might seem more feasible in the context of this comment.  "Futuristic bus that cars can drive under: the Straddle Bus"  Take a look!:) 

https://www.facebook.com/CollectiveEvolutionPage/videos/10154185262878908/?pnref=story