I'm usually a lurker here, but let me interrupt on this topic...
I've always been intrigued by the idea of a Front Range rail service between Trinidad and Denver because it fits two very important roles: 1) It provides valuable local service along an urbanizing corridor, and 2) it adds an important link in Amtrak's national network. A good comparison would be
Amtrak's Missouri River Runner that goes between St. Louis and Kansas City. It is almost exactly the length of of the proposed Fort Collins-Trinidad route (280 rail miles), it connects with Amtrak long-distant trains on both ends (connecting Amtrak passengers account for
30% of all River Runner passengers), and it utilizes diesel locomotive-hauled trains running over freight rail tracks. It's ridership isn't all that high (less than 500 passengers per day) but that's not terrible considering there are only 2 round trips per day. Since the 'joint line' south of Denver is famously congested with coal trains, I don't think CDOT will be able to run many more trains than that, at least not without significant investments in capacity (adding/lengthening sidings and double track).
Another comparison could be the
Pacific Surfliners, which go between San Diego and San Louis Obispo, via Los Angeles - a station that is also not a through-station. Because trains need to reverse in and out of that station, Caltrans has ordered push-pull versions of the Siemens trainsets used on the Brightline High(er) speed Rail project in Florida:
Another reason I like this comparison is because the Surfliner corridor has been a work-in-progress ever since it was first created, with a governing body called
LOSSAN receiving a small but constant amount of funding, allowing them to make continual updates to the corridor infrastructure (bridge replacements, double-track, new sidings, new stations, faster straighter track, etc.). This has allowed for an increase in frequency over the years that has caused ridership to increase. I think that even if a Front Range Rail service starts with only one or two round trips per day, that will be enough to get it established enough for CDOT to justify the cost for improvements to the line allowing even greater frequency. The virtuous cycle.
I think this train line is a very good idea. I just hope that the Amtrak National Network is still in place by the time service begins.