[6][12] From the A line's opening in April 2016, until mid-2018, there had been operational issues with the crossing gates due to software problems, resulting in frequent delays.

RTD made progress correcting this, along with the use of traffic guards, [13] earning the project a slot on Westword's 2016 Colorado Hall of Shame.

In June 2018, the FRA (Federal Railroad Administration of the Dept of Transportation) approved a plan to remove the flaggers monitoring the crossing gates along the A Line.

This approval also allows local jurisdictions to submit requests to the FRA to establish "quiet zones", removing the need for trains crossing through the gates to blow their horns.

[15] As of February 2019, approval for "quiet zones" at nine of the line's crossings has been granted, to be in effect on March 1, 2019; see Normal Whistle Codes.

Having left the Union Pacific corridor, the viaduct then descends to a station at the existing Park and Ride at 40th Avenue and Airport Boulevard.

Turning north, the line crosses over Peña Boulevard adjacent to DIA runway 7/25 and then runs east between the airport secure area and 78th Avenue.