RTD celebrates 20 years of connecting downtown and southwest Denver by rail

In 1994, RTD’s first rail line—the Central Corridor or “D Line”—opened in Denver. The D Line originally connected 30th · Downing Station to I-25 · Broadway. This was the first segment in a master plan that will eventually connect downtown Denver to C-470 · Lucent in Highlands Ranch.

We celebrate the next phase today, internally referred to as the Southwest Corridor, which opened in 2000 and extended the D Line to Littleton · Mineral Station.

D Line train stopped at Englewood Station circa 2000

Here’s how the Southwest Corridor developed and an overview of future plans:

D Line Extension

RTD conducted the Southwest Corridor Alternatives Analysis/Major Investment Study in 1992 to identify rapid transit alternatives to automobile traffic along South Santa Fe Drive between downtown Denver and Littleton. After conducting several scenarios light rail was selected because of the alignment and ease of integration with the existing portion of the D Line. Five years later, in 1997, groundbreaking for the corridor was on Jan. 21.

The extension added 8.7 miles and 5 stations through Englewood, Sheridan and Littleton. This part of the extension allowed those in southern Denver suburbs the opportunity to avoidtraffic on Santa Fe and commute by train.


On July 14, 2000, riders on the D Line took the inaugural trip that took them from downtown Denver through the southern portion of the metro area.

Attendees during the grand opening of Englewood Station on the D Line

In 1999, the original 5.3-mile D Line carried approximately 16,118 passengers every weekday. D Line ridership totaled 3,004,904 in 2019 (11,513 average riders per weekday).

C Line Integration

The C Line opened on April 5, 2002 as part of the Central Platte Valley extension which would eventually include the E and W lines in 2006 and 2013, respectively. The C Line starts at Union Station and travels southeast while providing convenient access to the major sports team portion of Denver. It begins to run along the same tracks as the D Line starting at 10th · Osage Station.


In 2018, total ridership along the Southwest Corridor was 5,791,687 passengers (22,190 aver riders per weekday).

Southwest Corridor Expansion

Through the 2004 voter-approved FasTracks initiative, RTD was given the greenlight to extend the C and D Lines down to Highlands Ranch. This will extend the line south by 2.5 miles while adding one station, C-470 · Lucent. The station will have 1,000 parking spaces. Project design and construction will commence when funding for the extension is secured.