RTD's train from Union Station to Denver International Airport on a test run.

(Hart Van Denburg/CPR News)

Denver Transit Partners, the private business that runs RTD’s commuter rail lines, has a rocky relationship with the transit agency.

Ongoing mechanical issues and regulatory delays with the A Line from Union Station to Denver International Airport mean that it and another line could miss an important deadline, and that has Moody’s worried that the RTD could terminate its contract with A Line operator Denver Transit Partners.

CPR’s Nathaniel Minor reported that Moody’s issued a warning to bondholders about the situation, and tells Colorado Matters what that means, why it matters and what's next.