The Federal Railroad Administration has granted the Regional Transportation District a 90-day waiver extension to allow the A and B lines to continue operating while they work to fix crossing gates that are coming down too early and staying down too long.

The University of Colorado A Line has operated under a temporary waiver from the FRA since it opened on April 22. The waiver was set to expire on Nov. 5 -- three weeks later than an earlier deadline that was extended by the FRA.

The earlier deadline allowed the train to operate while RTD and the Denver Transit Partners tried to fix glitches in the software system that controls the crossing gates at intersections along the A line. Flaggers have been placed at each crossing to monitor and control traffic in case gates stay down too long.

"It's much more of a technical glitch than anything," RTD spokesperson Nate Currey said to 9NEWS. "I think it's important for viewers to remember this is the first time ever in history that we've built anything like this with this safety system in place."

Flaggers will continue to stay in their locations until the issues have been resolved and correct crossing gate down times are fixed to comply with federal requirements.

The FRA gave this statement about the 90-day extension:

“Last week, RTD presented a plan to resolve the timing issues at its railroad crossings. FRA has granted RTD permission for another 90 days to use flaggers at the crossings, with additional conditions, while RTD works to implement this solution. During that time, RTD must continue twice weekly meetings with FRA's regional staff and also attend monthly face-to-face meetings in Washington to update FRA on its progress. RTD will be required to continue verifying that its flaggers are properly trained and are fully performing their duties.”

DETAILS: Read more about the decision at the Denver Business Journal

Under the new extension, DTP must implement plans that were presented to the FRA staff Oct. 28.

"We're confident that we'll be able to get these remaining issues fixed. We've got a good game plan going forward," Currey said.

RTD will meet with the FRA's regional twice a week, and the national office one a month, to give status updates.

Currey also said the G-line may no longer open in fall this year, as has been planned. There's a chance the launch won't happen until next year, even, as issues with the A-line and B-line are resolved.

RTD says the A Line has a weekly ridership of 18,000 passengers, which exceeds their first-year-end projections of 18,600 passengers. The B Line has 1,480 daily passengers, also ahead of its projected 800 passengers.