One of the more disturbing things raised in this post below about highway/transit shenanigans in Houston is the fact that they're trying to build over a railroad right-of-way. That's quite the shame. One of the main difficulties of building any project - highway or transit - is assembling the land from A to B. There are lots of abandoned or freight-only railroad right of ways still scattered around the country. And, when they exist it's pretty inexpensive to get a new system up and running, even if the track/wires/etc... are no longer there or functional.
Where I lived as a lad they closed down a rail line that had been there forever and slashed up the right-of-way. 30 or so years later they're considering a new route (unlikely to happen anytime soon) which would mostly parallel the old route. But, assembling the land required will be a hideous and perhaps, in the end, prohibitively expensive endeavor.
I agree with some who said in comments that the question isn't if cities will construct more rail projects, but when. But, once areas are too built up the costs escalate rapidly, particularly if the existing right-of-ways are demolished.
