Metro Denver’s public transportation system needs more than $1 billion to expand its rail service to more areas across the region, notably to the north.

The Regional Transportation District on Monday released a draft of its comprehensive 2025 Finishing FasTracks Report, part of an already 20-year-old program to expand the service across the metro Denver region.

In its draft, transportation officials estimated RTD needs $1.6 billion in capital and operating costs to complete the FasTracks program across four unfinished and unfunded expansion projects by 2034. 

That includes more interest in expansion up north.

“RTD recognizes that this report is the first step in bringing the 20-year-old FasTracks plan to fruition,” Debra Johnson, RTD’s General Manager and CEO, said in a statement Monday.

The cost, however, is already over budget.

Since voters approved FasTracks in 2004, RTD has already completed 75% of its projects. Originally, the program was expected to cost $4.7 billion, which, to date, has ballooned to $5.5 billion in costs for the first 75% of construction, according to RTD.

FasTracks has, so far, resulted in 25 miles of new light rail track, 53 miles of commuter track, bus rapid transit implementation, the Flatiron Flyer and new Union Station train platforms with an underground bus concourse.

But big hurdles remain in finishing the voter-approved transportation project.

“Significant challenges exist related to completing the Northwest, North Metro, Southwest, and Central corridors, including very low growth in sales and use tax revenues that started during the Great Recession, escalating construction costs, increases in raw materials costs and supply chain and labor market challenges,” RTD officials said Monday.

$1.6 billion more on new rail lines?

For years, RTD has focused its rail service in other areas of metro Denver, expanding as far southeast as Lone Tree, as far west as Golden and as far north as Thornton.

Now, RTD officials are looking elsewhere.

RTD’s remaining 25% of FasTracks relies on four rail projects:

• The N Line will be extended 5.5 miles farther in Thornton. The first 13 miles of the proposed 18.5-mile line provides service from Union Station through Denver, Commerce City, Northglenn and Thornton. It will eventually extend into north Adams County. 
• A proposed 2.5-mile expansion of the D Line from Mineral Station into Highlands Ranch.
• Extending the L Line from 30th and Downing Station to the 38th and Blake Station.
• Extending the B Line beyond Westminster to and from Longmont.

RTD officials said state funding could potentially contribute toward a limited completion of FasTracks projects.

If all goes as expected, Colorado could potentially contribute $441 million for projects between 2026 and 2034, monies that need to be approved by separate state governing boards, according to RTD.

“RTD was not able to identify any additional funding currently eligible to cover the remaining estimate of $1.159 billion needed to complete the original FasTracks plan,” an RTD spokesperson told The Denver Gazette in an email.

“Additionally, ongoing funding would still be required for operation and maintenance of the rail corridors, as well as asset renewal,” RTD officials said in the news release.

RTD is asking the community to provide feedback on the draft report online.

Johnson, RTD’s CEO, said the transportation agency “welcomes the opportunity to build upon the current momentum of joint rail service planning.”

She said RTD is “working with the Governor’s Office, Colorado General Assembly and other stakeholders across the Denver metro area to advance discussions about how best to optimize the sustainable expansion of public transport in the region.”