Idea for Front Range Commuter Rail

[SIZE=12pt]I’m just thinking out loud here:[/SIZE]

[SIZE=12pt]I know a huge challenge to having north-south Front Range commuter rail is that the existing corridor is maxed out with freight traffic. Likewise, there simply isn’t room along the entire corridor for a new, separate set of commuter rail tracks (such as the FrontRunner tracks next to the UP line in Utah). [/SIZE]

[SIZE=12pt]While it’s a shame that Colorado doesn’t have something like the Frontrunner, I wonder if the next best thing would be to implement a several times daily service similar to the regional Amtrak trains in California. If current freight traffic makes this idea unworkable, perhaps additional tracks/sidings could be constructed along segments of the corridor that do have the extra room. Of course BNSF and the state/RTD would have to agree on who pays for what and how the additions are constructed and utilized, which could be a huge obstacle. [/SIZE]

[SIZE=12pt]Perhaps this idea has already been pitched and dismissed, or objectively isn’t worth pursuing. But I thought I’d throw it out there just in case. [/SIZE]

Like you said, it's mostly a matter of room and traffic.
Utah was lucky because UP had a lot of surplus track they were willing to let go cheap, but if you have a lot of traffic on the Front Range that's probably not an option. With the traffic you describe your best bet would be double tracking (unless that has already been done) or a new right of way, which is difficult in a built up area.
On the other hand, there always seems to be room for another freeway, and a train line takes up a lot less space.