Our quest to find out if RTD is asking federal authorities for yet another waiver for the University of Colorado A Line is as inconsistent as the crossing arms that are causing some of the problems.

On Wednesday RTD officially requested a fourth waiver to allow the A Line to continue running.

The waiver, which was sent to 9NEWS by RTD Thursday afternoon, requests an extension "to allow for the review and approval of the Measurement and Performance Criteria Document."

This is essentially the last thing needed for FRA to sign off that the entire system meets the design standards that the blueprints said it would.

"The process of final closeout is going to go beyond the July 30 deadline. We requested another extension and we'll request as many as we need to until we get the process done," said RTD spokesman Nate Currey. "The light is at the end of the proverbial tunnel and we're happy to be there."

RTD had until Sunday to get approval from the Federal Railroad Administration, that the A Line's Positive Train Control and warning system is functioning within the regulations, or it had to request it's fourth waiver to continue operating. Without either, the FRA could choose, albeit unlikely, to shut down the train to the plane.

Positive Train Control is a computerized fail safe for the train system. The A Line is the first commuter rail line to try to operate with Positive Train Control from the start. It is supposed to help prevent the train from speeding, colliding, entering misaligned switches and entering "established work zones" when workers are on site.

The warning system relates to the crossing arms, lights and bells you see at each crossing.

RTD was granted federal approval of the A Line on Apr. 19, 2016. It requested waivers of compliance to continue running the train despite not meeting federal requirements three different times already, which were approved to take effect on the following dates:

-Nov. 5, 2016
-Feb. 1, 2017 (Follow-up coverage on Feb. 2, 2017)
-Apr. 27, 2017

The FRA still needs RTD to fix the at-grade crossings to drop the gates within designated warning times.

RTD has previously told 9NEWS that the gates are going down in plenty of time, however they either come down too early or stay down too long at the at-grade crossings.

9NEWS has been asking RTD and the FRA since Monday if a fourth waiver had been or was going to be requested.

On Monday and Tuesday, RTD said no waiver was requested yet.

Thursday morning, RTD told 9NEWS that a waiver was submitted for the B Line to Westminster, but no waiver had yet been requested for the A Line. Meanwhile, the FRA confirmed a waiver was submitted.

In a statement to 9NEWS, an FRA spokesman wrote:

"FRA received petitions to extend the Denver RTD waivers for the A and B lines. We are reviewing the requests and will make a decision before the current waivers expire on July 30. Denver RTD continues to make significant progress on the performance of the grade crossings on both lines. FRA and Denver RTD will use the additional time afforded by the waivers to continue evaluating the system to make sure it operates safely."

Petition for Extension a- Line Waiver by 9news on Scribd

RTD's second waiver from the FRA said that the crossing arms would have to work correctly each time at each of the at-grade crossings for seven consecutive days.

Whether or not the FRA approves the A Line or grants another waiver, a misconception is that the flaggers will go away and the horns will stop blowing at the crossings that go through what are supposed to be "quiet zones."

The Colorado Public Utilities Commission has to approve RTD's crossings as well. RTD has previously submitted a design plan which has already been approved by the PUC. Once crossing testing with the PUC is complete, RTD has to file a completion letter, which will then trigger the Commissioners to make a decision about the requirement for flaggers.

The sounding of the horns requires the city or county to apply to become a quiet zone. Those applications can't even be considered until the FRA and PUC give the OK.