Colorado desperately needs something like this. I hope it passes. Although the service times are few and far between, people will make it work, I guarantee it.
Utah has something similar between its southernmost city in the greater Salt Lake area - Provo- and up to Ogden. I believe it also shares the lines with freight and while there are delays if a freight train is going somewhere (passenger trains give way), it's still very popular.
This sounds absolutely fantastic. If I could have ridden a train from Boulder to C. Springs in college, I would have never needed a car. With the number of commuters that live outside of Denver and commute to it (or more rarely in the other direction) having this option should greatly relieve the number of vehicles on I25