The Skyway Bridge, seen here under construction in December 2017,  will carry RTD N Line commuter trains through the northern metro for just under two miles. 

(Nathaniel Minor/CPR News)

​​RTD estimates its future commuter rail line from Denver to the northern suburbs won’t open until the spring of 2020, a delay of approximately six months beyond last year’s estimate of late 2019.

The new timeline was published in advance of an RTD board committee meeting set for Tuesday. And the new approximation is just that — an approximation, said Lisa Trujillo, RTD’s project outreach manager for the N Line.

“That’s a ballpark figure,” Trujillo said. “We are not ready to announce any date at this time.”

RTD initially set an opening date of 2018 when construction began on the line four years ago. The transit agency and its contractor filed lawsuits against each other last year over the delays before the two parties entered arbitration.

The 13-mile line will carry passengers between Northglenn and Union Station in downtown Denver. Northglenn Mayor Carol Dodge said she wasn’t surprised by the latest delay.

“We all figured it was still going to be 2020, because they really haven't kept their promises on many of the opening dates of all the other lines,” Dodge said. “For two more years we'll be sitting here with stations that have got no trains coming to them."

Northern and western metro leaders have lodged complaints with RTD for years over delays associated with rail lines promised in the 2004 FasTracks vote. And at this point, Dodge isn’t sure what else she can do as an elected official.

"We can always advocate for ourselves,” Dodge said.”I'm just not sure that it makes a difference based on what's happened."

Trujillo said construction on the N Line is 85 percent complete. The line will also be the first commuter rail line operated and maintained by RTD; the A, B and G lines, when that opens, are operated by Denver Transit Partners for RTD. Trujillo said the opening date could be affected by how smoothly tests go, as well.

"We just ask for patience as we work through construction in getting this line stood up for operation," she said.