The new R Line connecting Aurora to the rest of RTD’s rail system is expected to open Feb. 24, but the transit agency still hasn’t resolved software issues on the University of Colorado A Line crossings and will seek another waiver from the feds to keep it operating.

The R Line connects 10.5 miles of new light rail to existing track at Nine Mile Station. It will run south from Peoria Station in Aurora, following Interstate 225 to Belleview Station on the existing track in southeast Denver. From there it will travel to Lincoln Station in Lone Tree.

“Basically, this brings Aurora into the fold, brings them into the family,” Regional Transportation District spokesman Nate Currey said Tuesday of the R Line, which will serve eight new stations including the University of Colorado Anschutz Medical Campus.

The line was originally scheduled to open late last year, but was delayed, Currey said, “to make sure everything was squared away.”

RTD’s opening of its commuter rail A Line train from Union Station to Denver International Airport last year was plagued with problems. RTD faced a possible suspension of service on on the line in early November last year, a deadline the Federal Railroad Administration had set for fixing the timing of gates at crossings along the 23-mile long A Line.

The FRA granted a 90-day waiver for the A Line, which expires Saturday..

RTD is now requesting another extension. Currey said he didn’t know the length of the delay requested.

The G Line, which will travel will travel between Union Station and Wheat Ridge, was originally scheduled to open last year, and has been delayed, because it has the same at-grade crossing technology as the A Line. It is also covered under the waiver.

The glitch in software that closes at-grade safety gates at vehicle crossings along the A-Line route causes gates to close seven seconds before a train arrives, and open five seconds after it leaves, Currey said.

But the system is static. As designed, the software doesn’t take into account potential delays, or early arrivals caused by train operators unexpectedly accelerating or decelerating, passenger boarding and departing times, or changes in movement of vehicle traffic.

Changes are being made to the software to compensate for those variables, Currey said.

Trains on the A Line are now testing the system. “We are getting there, but we are not quite where we want to be,” Currey said.

“No system has ever done this before, we are the first ones out of the gate to build it from the ground up. It’s more complicated than anyone expected it to be.”