Denver’s Regional Transportation District (RTD) celebrated the 10th anniversary of the A Line, the commuter rail service known as the Train to the Plane.

The 23-mile A Line runs from Denver Union Station (DUS) to Denver International Airport (DEN), offering customers fast, reliable connections for domestic and international travel. With more than 59,400,000 boardings since the service’s debut, the A Line’s utilization surpassed that of all other RTD rail services in 2025, the agency reported.

Celebrating 10 Years

To mark a decade of the A Line, RTD held a media conference with speakers including its GM/CEO Debra A. Johnson, RTD Board Chair Patrick O’Keefe, Aurora Mayor Mike Coffman, and Denver Transit Partners (DTP) Project Manager and CEO Nate Morgan.

“Celebrating the 10th anniversary of the A Line is truly a milestone for the entire region. From day one, this service has strengthened connections and created opportunities for customers and visitors alike, expanding access to destinations throughout the Denver metro area,” Johnson told attendees. “The launch of the A Line in 2016 made it easier than ever to reach key activity centers while supporting economic growth and sustainable mobility.”

When the A Line launched in 2016, it became the first commuter rail service completed under the 2004 voter-approved FasTracks project. Customers aboard the electric commuter rail train can skip bumper-to-bumper traffic and airport parking costs, all while being conveniently dropped off near the main airport terminal. The service operates at speeds up to 79 mph, faster than the light rail’s top speed of 55 mph, for a 37-minute trip to DEN from DUS. 

Successful Ridership Numbers

The Train to the Plane has maintained strong utilization throughout its decade in service. During the COVID-19 pandemic, the A Line led the nation in terms of commuter rail utilization and revenue hours, according to a 2024 report.

In January 2026, the most recent month for which data is available, A Line ridership increased 17.7% compared with the same time last year. In 2025, ridership increased by 4.3%, the highest increase among all RTD commuter rail lines. From January 2025 through February 2026, boardings totaled 7,166,178, bringing total ridership close to 60 million since its launch, said officials.

Because timely service is crucial for making travel connections, the A Line’s notable on-time performance averaged 90% overall last year and 91% as recently as March 2026.

On-time performance measures how often vehicles arrive at stations according to the posted schedule. Service availability — the percentage of trips that operate as scheduled — reached 97.7% for the A Line in 2025. The combined metrics make the A Line a reliable solution for customers to bridge travel connections to and from the airport.

For customer ease of access, the A Line departs every 15 minutes from DUS from 6 a.m. to 8 p.m. and 30 minutes during early morning and late evening hours, identical to the service hours when the A Line first launched in April 2016.

The Road to the A Line

To deliver the A Line, RTD and its concessionaire operator, DTP, entered into the first public-private partnership for transit in the US. The A Line was the first of three commuter rail lines to open in Denver, made possible by that partnership. 

Plans for RTD’s first commuter rail between downtown Denver and DEN began in 1997. RTD conducted an investment study to evaluate recommendations for commuter rail, light rail, and highway development plans. The A Line’s final track was constructed in 2014, followed by testing and safety compliance in 2015 ahead of the A Line’s 2016 debut.

 RTD designated the letter “A” to be reserved for the “Airport” commuter rail line almost 30 years ago. Crews on the A Line worked over seven million hours to complete the project, averaging 800 employees per day, said officials.

Since the line’s 2016 launch, the cost of an Airport Day pass has increased by only $1. Today, a $10 Airport Day Pass provides full-day travel for customers who arrive in Denver and want to continue their journey using RTD’s mobility options to reach their next local destinations.