Covering the
rail platforms but not necessarily the
bus depot makes it a lot cheaper than these big bus depot canopies I've been pulling.
Calgary is a cool example.
Here's another: Dallas has a standardized canopy that I think is great. It's not exactly comparable to what I-25/Broadway would need because 1) it's for side platform stations, and 2) I don't think Dallas has any 3-track stations. Also, cost info for only the canopy is hard to find, since the rest of our station (tracks, platforms, etc) is already in place. But I'd ballpark this at only a few million.
They also have a DIA-tent-fabric-style version that's probably pretty cheap, and would go well in Denver:
If you just want to cover the platforms, and are happy to leave the tracks to the elements, then something like this would be super cheap (IDK exactly how cheap, but definitely affordable):