An RTD commuter rail car enters DIA's transit center under its own power. The East Rail Line connecting DIA to downtown Denver is scheduled to open sometime in mid-2016.

(CPR News/Nathan Heffel)

RTD’s commuter rail line to Denver International Airport marked an important milestone Friday when two commuter rail cars entered the station at the airport under their own electric power.

The test marks one of the final stages before the East Rail Line opens to the public in mid 2016.

During prior trips, the cars were pulled by another test engine. RTD’s Kevin Flynn said the cars arrival at the transit terminal mark a game changing moment not just for the line, but the agency itself.

“Today is the start of testing. But what you have is a line that we believe people from all over the metro area will likely use, as opposed to the rest of the system that serves individual corridors,” Flynn said.

Under driving rain, the first two RTD commuter rail cars for the East Rail Line to Denver's Union Station arrive at DIA's transit center on April 17.

Stu Williams, DIA's senior vice president of the hotel-transit center, says a train connecting DIA to Denver was always in the airport’s master plan.

“So today is a monumental moment because now that vision is really close, and ultimately we have completed the vision of that master plan,” said Williams.

RTD will slowly ramp up testing of more commuter cars with the line opening sometime in mid 2016. Once service begins, the commuter trains will be operated by Denver Transit Partners, part of the public-private partnership formed to construct the line.

And now that full testing has begun, people will start to see much more activity on the tracks.

“We’ve got to put 1,000 hours on each train car before a member of the public is approved to ride,” explained Laura Rinker, communications manager with Denver Transit Partners. “We want to make sure that people aren’t throwing anything at the overhead power lines."

Unlike traditional light-rail, which uses 750 volts of DC power, the commuter rail uses 25,000 volts of AC power.

RTD says that once the line is in operation, a trip between Denver’s Union Station and DIA will take approximately 35 minutes. The Westin hotel located at DIA's transit center will open later this year.