A Line (RTD)

A Line

Company type	Commuter rail service
Industry	Public transportation
Founded	April 22, 2016 (2016-04-22)
Founder	Regional Transportation District (RTD)
Headquarters	Denver, Colorado , United States
Area served	Denver metropolitan area including Aurora and Denver International Airport
Owner	Regional Transportation District (RTD)
Website	www.rtd-denver.com/services/rail/a-line

The A Line (previously known as the University of Colorado A Line due to sponsorship agreements) is a commuter rail service operated by the Regional Transportation District (RTD) that connects downtown Denver with Denver International Airport (DIA), also serving parts of the Denver metropolitan region including Aurora. During its development phase, it was referred to as the East Rail Line, though it is widely identified simply as the A Line. Despite its previous naming rights association, this line does not provide direct service to the University of Colorado Denver campuses.

History

Discussions about establishing mass transit between Downtown Denver and Denver International Airport date back to the 1980s, coinciding with the airport’s initial proposal. Momentum for the project increased in 1997 after a Major Investment Study recommended several improvements including fixed-guideway transit, highway expansion, and other enhancements. The plan was incorporated into the FasTracks transit expansion program approved in November 2004 and subsequently received Federal Transit Administration endorsement in November 2009. In July 2007, electric propulsion was selected over diesel-powered trains due to advantages in speed and environmental impact.

The RTD assigned the letter "A" to this line to signify its service to both the airport and Aurora. Construction began with a groundbreaking ceremony on August 26, 2010. As the second line developed under FasTracks, the East Corridor was built through the Eagle P3 public–private partnership model. Testing of the first electric multiple unit railcars commenced on April 3, 2015.

Passenger operations officially launched on April 22, 2016. Early service experienced technical difficulties related to crossing gate software that caused gates to close prematurely and remain down too long, resulting in frequent delays and traffic congestion. RTD implemented software updates and deployed traffic personnel at crossings to mitigate these issues. Despite corrective measures, the project faced criticism and was featured in Westword’s 2016 Colorado Hall of Shame. The complexity of managing shared crossings with Union Pacific freight lines contributed to operational challenges.

In June 2018, the Federal Railroad Administration authorized removal of flaggers at crossings and permitted local governments to request "quiet zones," which exempt trains from sounding horns at designated crossings. By February 2019, nine crossings had been approved for quiet zone status effective March 1, 2019.

Route

The A Line runs primarily alongside Interstate 25, Interstate 70, and Peña Boulevard, making use of an existing Union Pacific Railroad corridor extending eastward from downtown Denver before veering north along Peña Boulevard through a newly constructed right-of-way. Although Peña Boulevard’s wide median was originally intended for rail transit use, the final East Rail Corridor alignment shifted off from the highway’s right-of-way.

Starting at Denver Union Station, the line passes near Coors Field before reaching a station at 38th and Blake Streets, which will also serve future Central Corridor expansions. It then heads east along 40th Avenue, skirting the Denver Union Pacific Intermodal Yard and continuing along Union Pacific tracks to a station located at 40th Avenue and Colorado Boulevard. After passing beneath Colorado Boulevard, it parallels Smith Road with a stop at Central Park Boulevard within the revitalized Stapleton neighborhood. Upon entering Aurora, it arrives at Peoria station, which is shared with the R Line.

Traveling further east alongside Smith Road, the route passes under Peoria Street and Interstate 225. Approaching Airport Boulevard, it ascends on a viaduct that crosses over Union Pacific tracks, Airport Boulevard itself, 32nd Avenue, and Interstate 70 before descending to a station situated at the Park and Ride facility near 40th Avenue and Airport Boulevard. Reentering Denver city limits, the line follows along Peña Boulevard’s eastern side to a stop at 61st Avenue.

Continuing northward adjacent to Peña Boulevard, it crosses over E-470 and Peña Boulevard close to DIA’s runway 7/25. The track then proceeds between the airport’s secure zone and 78th Avenue before spanning Peña Boulevard’s terminal exit lanes to conclude service at the DIA Hotel and Transit Center station next to Jeppesen Terminal.

Stations

Fare zone	Station	Municipality	Opened	Key connections & remarks
Local	Template:Rtds	Denver	April 22, 2016	Template:Rint Template:RintTemplate:RintTemplate:RintTemplate:RintTemplate:Rint Template:Ric Template:Rint MallRide Template:Rint Flatiron Flyer
	Template:Rtds			Park and ride: 200 parking spaces
	Template:Rtds			Park and ride: 200 parking spots
	Template:Rtds			Park and ride facility with 1,500 spaces
	Template:Rtds	Aurora		Template:Ric Template:Ric Park and ride: 550 spaces available
	Template:Rtds			Offers park and ride with 1,079 spaces
	Template:Rtds	Denver		Paid parking with 800 spaces
Airport	Template:Rtds			Template:Rint Denver International Airport