The good and bad of Denver’s new airport transit line

Denver RTD A-Line map.

Denver RTD A-Line map.

Next time you fly into Denver, you’ll be able to hop on a train from the airport to downtown. There’s a lot to celebrate about this new transit line, and much to criticize. There’s plenty of effusive praise for Denver’s transit ambitions without much critical pushback in the popular press.

A few thoughts on the good and bad of the line and RTD’s rapidly expanding system, starting with the not-so-good.

  • This line is part of Denver’s large FasTracks system expansion. While ambitious in scope, many of the routing decisions are odd network choices. There’s a lot of reverse branching, use of freeway rights of way, and other opportunistic decisions to ease construction, but which may be regretted later.
  • FasTracks centers on Denver Union Station. DUS is a remarkable urban redevelopment project, but a huge missed opportunity in terms of transit operational design.
    • Union Station is now a stub-end terminal for regional rail trains, limiting the station’s capacity and preventing future intercity or regional rail use of the station.
    • Light rail trains stop 1,000 feet away from the regional trail platforms. The distance is creatively connected with an underground bus concourse, but the transfer environment is less than ideal – particularly given the almost-blank slate to work with.
    • Real estate development projects advanced before any understanding of the transit right of way needs, and have now forever closed those avenues for expansion. The real estate framework for expanding Denver’s downtown matured before the framework for transit expansion.
  • Rail service to Denver’s airport is important, but commentators often place too much emphasis on serving airports instead of overall improvements to the transit network. This is less true for Denver, given the systematic transit expansion as a part of FasTracks (and the network benefits therein).


Critiques aside, there’s a lot to praise with the airport line.

  • Frequent, all-day, electrified main-line rail service – much of it built in a greenfield right of way.
    • For all of the benefits of main-line rail as a means to offer rapid transit service, it’s great to see a project execute on those benefits
    • Electrification offers great promise for frequent transit – taking advantage of performance benefits from using electric multiple unit trains with quick acceleration, instead of diesel-powered peak-only ‘commuter’ trains.
    • Development of new regional rail transit lines along greenfield right-of-way opens up all kinds of planning possibilities for other regions.
  • The project demonstrates the benefits of risk-sharing public-private partnership deals. With the contractor responsible for long-term operating costs, their design efforts focused on the most efficient way to meet the parameters of the contract (all-day, frequent rapid transit service). For those reasons, the team embraced the electric commuter rail concept, opting for:
    • Mainline rail vehicles to better handle interactions with adjacent freight rail corridors and meet regulatory requirements
    • International standard electrification (25kV AC) to reduce the costs of substations while still providing the necessary performance
    • off-the-shelf procurement of a proven design (Silverliner V vehicles) to avoid development costs.


1 comment to The good and bad of Denver’s new airport transit line

  • steve

    thanks for digging into the details

    i criticized the distance from light rail to commuter rail terminals during the planning process and received pushback that planners “knew what they were doing”; there was also a promise of a moving walkway through the underground bus station linking the terminals, but then, as often happens, the walkway was axed for budget reasons; the result is an additional 10-15 minutes of carrying luggage for many trips to/from the airport

    on the “stub end” and real estate decisions, not sure if you are alluding to the fact that the area used to be a huge train yard with through routes to the south; heavy rail still has a through route nearby, and though the Colorado Rail Relocation Implementation Study was “inactivated” in 2012, private developer Bob Briggs has recently resurrected the idea of moving freight rail out of central Denver; this would “free up” these heavy rail tracks and possibly resurrect hopes for a better connected Front Range rail system

    on the other hand, how could that happen when the commuter rail line to Boulder/Longmont, for which those residents have been paying increased taxes since 2004, won’t be finished until 2044?

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