Northwest Rail

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Completing the B Line to Boulder, Longmont and beyond…

Promised in the RTD FasTracks sales tax vote in 2004, the 41 mile Northwest Rail Line is intended to connect Denver to Boulder and Longmont via commuter rail. However, it has experienced several delays and challenges in development including cost increases that RTD has struggled to find ways to fund.

The original plan was to pay BNSF, who own the tracks from Westminster to Longmont via Boulder, to double-track the line and electrify it at 25kV 60Hz AC, which is what the rest of the RTD commuter rail system uses. While the double-tracking wasn’t such a big deal for a large Class I railroad, the electrification was asking BNSF to do something it had practically zero construction and operating experience in return for no benefit for freight train operations, which would remain diesel powered.

The result was that the costs quoted ballooned from the $461m original estimate to complete the northwest rail one in 2003 (before the FasTracks vote) to $1.5bn in 2018. With polling showing that voters were unlikely to approve further sales tax increases, RTD started projecting that they wouldn’t have funds to complete the line until 2042 (now revised to 2044). These dates are clearly unpalatable for politicians in Boulder and Longmont, who point out that their communities have now been paying their fair share of FasTracks sales taxes for 20 years with little progress on the line to show for it.

Because of the issues, the uncompleted B line to Boulder and Longmont remains the No. 1 source of ammunition for RTD’s detractors who accuse the agency of breaking its promises to communities located northwest of Denver and wasting taxpayers cash.

The current B Line service…

Currently, only the first 6 miles of the B Line between Union Station and Westminster have been completed with trains running on a dedicated electrified single track in a shared right-of-way with BNSF. This section opened in July 2016 and offers an hourly service, all-day, seven days a week. Ridership has never necessitated the operation of more than a 2-car commuter train consists and the line suffers a poor station area layout at Westminster that makes connections to bus services inconvenient. In addition the transit orientated development (TOD) has so far failed to significantly materialize around the station and due to the low service frequency, most park-n-ride customers will opt to drive to one of the G Line stations a few miles south which currently enjoy double the number of trains.

Joint Service White Paper

In February 2024, the FRPR District, CDOT and RTD published a white paper outlining the opportunities available if all three parties were to pursue a joint service arrangement on the Northwest Rail corridor. The white paper makes the following key points:

• In December 2023, as part of the Service Development Planning process, the FRPR District Board Directors formally designated the existing BNSF rail line from Denver to Fort Collins (via Boulder and Longmont) as the preferred track alignment for FRPR north of Denver, which has also been accepted by the FRA.
• Near-term passenger rail service from Denver Union Station to Longmont can be accomplished by extending the service to Fort Collins to trigger the federal benefits available for intercity passenger rail, which are not available to commuter rail, and get a head start on the whole FRPR corridor.
• Because FasTracks committed to providing rail service from Denver to Longmont and RTD has been collecting funds for it (via the 0.4% sales tax approved by voters in 2004), there is a longstanding expectation of service and some funds available from the RTD FasTracks Internal Savings Account (FISA) that could be used.
• As well Infrastructure Investment and Jobs Act (IIJA) and RTD FISA funds, additional sources of funding will need to be identified. The white paper looks at a few possible options.
• The FRPR District, CDOT and RTD all have the power to enter into an intergovernmental agreement (IGA) to deliver passenger rail service on the Northwest corridor.

RTD Peak Service Study

In August 2024, RTD published results of its Peak Service Study which assessed an initial commuter rail service in the Northwest Corridor. The peak service concept is three trains in the morning from Longmont to Denver Union Station stopping at all stations and three trains back in the afternoon. The study then went on to identify corridor and regulatory challenges and constraints, infrastructure requirements, fleet (train vehicle) options, station site plans, platform configurations, concept designs, and the range of costs, benefits, and impacts of providing the service.

SB24-184 Legislative Requirements

In May 2024, Colorado Senate Bill SB24-184 Support Surface Transportation Infrastructure Development, became law. It contains a number of provisions and requirements for advancing joint service on the Northwest Corridor including:

• RTD is permitted to run trains beyond its district boundary north of Longmont provided it is reimbursed for all capital and operation expenses by a public body (Section 4).
• The FRPR District, CDOT, CTIO and RTD must provide a report detailing an implementation plan for construction and operations of the Northwest Corridor by September 30th, 2024. (Section 6 (a))
• The FRPR District, CDOT, CTIO and RTD should decide whether to create a standalone legal entity (such as a ‘Colorado Rail Authority’), separate legal entity or sign an IGA to to create a cooperative unit. Once decided they should either create the new entity or sign an IGA by December 31st, 2024. (Section 6 (a)(II)).
• The FRPR District, CDOT, CTIO and RTD must provide a report detailing a plan to begin providing FRPR service by January 1st, 2029. (Section 6 (b)).
• If FRPR service on the corridor has not begun by January 1st, 2029, the FRPR District, CDOT, CTIO, RTD and any separate legal entity provide a report detailing the reasons why and a detailed plan for providing service. This report must be updated and reissued every six months until FRPR service begins (Section 6 (c)).

Joint Service Implementation Plan

On September 30th, 2024 the FRPR District, CDOT, CTIO and RTD published the Northwest Fixed Guideway Corridor Implementation Plan and Report as required by SB24-184. The plan and report document included:

• A summary of all ongoing and completed studies and service development plans that could be leveraged to accelerate approval and permitting for the Northwest Corridor.
• Confirmation of and reasoning behind the decision sign an IGA as opposed to creating a standalone legal entity (such as a ‘Colorado Rail Authority’) or other separate legal entity to create a cooperative unit between the parties.
• Details of the financial study that has been initiated to assess the feasibility of delivering intercity passenger rail starter service with three to five daily roundtrips from Denver Union Station to Fort Collins.
• An evaluation of potential operators for the Northwest Corridor which concluded both Amtrak and non-Amtrak operators may be viable for joint service and expanded Front Range Passenger Rail service.

2024 CRISI Grant

In October 2024, CDOT was awarded a $66.4M Consolidated Rail Infrastructure & Safety Improvements (CRISI) program grant from the FRA to improve existing freight service and support developing passenger rail services on the Northwest Corridor.

The award supports a $94.3M project, with the State of Colorado providing $27.9M via its IIJA Cash Fund, to conduct the following activities:

• Design and install PTC on 10.2 miles of BNSF-owned track between Broomfield and Westminster, MP 4-16.4.
• Design and construct an additional siding from MP 10.2-12 to provide a location for trains to be stored, mitigating track conflicts.
• Improve three different highway-rail crossings at County Road 10E, N 115th Ave, Vermillion Road through the construction of quad gates, lights, raised medians, and warning signals.
• Conduct planning to support potential future grade separations of two crossings at (SH 66 and SH 119).

Intergovernmental Agreement (IGA)

The Intergovernmental Agreement (IGA) between the FRPR District, CDOT, CTIO and RTD was in progress as of March 2025.

Joint Service Report

On March 1st, 2025 the FRPR District, CDOT, CTIO and RTD published an updated Northwest Fixed Guideway Corridor Implementation Plan and Report as required by SB24-184. The plan and report document included:

• An explanation that during 2023-24, a convergence of factors – new state revenue streams, federal funding opportunities, and political will across the region emerged, and those factors presented an unexpected opportunity to expedite the delivery passenger rail service on the Northwest corridor.
• The IGA creates a 12-member joint service executive committee (JSEOC) made up of the Principals of the six Parties which are the FRPR District, CDOT, Colorado Transportation Investment Office (CTIO), Clean Transportation Enterprise (CTE), the Governor’s Office and RTD.
• Eight stations are identified in Joint Service Plan – Denver Union Station, Downtown Westminster, Broomfield, Louisville, Boulder, Longmont, Loveland, Fort Collins.
• CDOT’s consultant HNTB has completed Rail Traction Controller (RTC) modelling for 3 and 5 round trips per day.
• Proposed infrastructure has the goal of holding BNSF freight railroad operations harmless from proposed passenger operations and protects the on-time performance of passenger operations.
• Implements FRA-required Positive Track Control (PTC) signaling system.
• 5-car train consist (1 locomotive, 3 coach cars, 1 non-powered control unit) providing 200 seats.
• Annual seats provided assuming 3 round trips per day, 7 days a week is 445,000.
• Estimated cost of Joint Service Plan is $885M.

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