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The infamous and elusive B Line to Boulder — and beyond

It’s a question Coloradans have been asking themselves for decades: When will we finally see the promised RTD train connecting Denver to Boulder and Longmont?
Posted: 5:45 PM, Apr 12, 2023
Updated: 2023-04-14 11:53:11-04
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DENVER — It’s a question Coloradans have been asking themselves for decades: When will we finally see the promised RTD train connecting Denver to Boulder and Longmont?

Voters said they wanted it nearly two decades ago, and they’ve been paying taxes for it — and other public transportation initiatives — ever since. But, ballooning costs and construction concerns have continuously delayed its completion and now, nearly two decades since the first vote, there is no sure end in sight.

In 2004, Colorado voters approved a 0.4% tax increase to fund the FasTracks program, which envisioned public transit throughout the Front Range. Quite a bit of FasTracks has come to fruition, but the completed B Line to Boulder and Longmont, also called the RTD Northwest Rail Line, has been a glaring exception.

A lot has changed since 2004, including the estimated price tag for the B line expansion. The most recent projection in 2018 put the price tag at $1.5 billion and with a completion date in 2042. With that, we went 360 to find out how some Coloradans with different perspectives now look at the B Line, and its potential role in a future for Denver that is less car centric and more environmentally friendly.

Justin Bai, the Transit Guy

Justin Bai waits at Union Station
Justin Bai, a student and employee at CU Boulder, waits for a bus at Union Station

For many people, Denver’s Union Station is a means to an end — a way to get from point A to point B for their work or play.

For Justin Bai, it's a lifestyle.

“I never got my driver’s license, and so public transportation has just been a day-to-day part of my life,” Bai told us from a Union Station bench, donning an RTD W Line hat. “For me, public transportation is more than just, you know, a bus you can take. I think it’s actually a really important part of building a sustainable future.”

Bai calls himself a “reverse commuter.” He lives in Denver, and works and studies at CU Boulder. Three times per week, he treks to Union Station to begin his commute. He said he would like to be able to hop on the promised B Line to Boulder, but as it is still just a dream, he for now relies on RTD’s Flatiron Flyer bus.

“The B line is a train that is supposed to go all the way to Boulder and Longmont, but currently it only goes as far as Westminster. I would like to see that change,” Bai said. “I mean, I happily take the bus that goes to Boulder. But I always think it’s important to have multimodal options and to expand our transit system for the greater population.”

A possible plan B for the B Line

Patrick Stanley with RTD
Patrick Stanley, who serves as project manager for RTD's Northwest Rail Peak Study

In recent years, RTD has been on a fact-finding and opinion-finding mission. After its 2018 study showed a huge price tag and long timeline, RTD has been studying the feasibility of the vision that has been promised to voters.

We asked Patrick Stanley, project manager for RTD’s Northwest Rail Peak Study, if the question over the B Line is still one of when we will see its completion or if it is now a question of if we will see its completion.

“You know, I don’t think we can answer that definitively at this point,” Stanley said. “So, what we’re going to do at the end of this study is we’ll have some options.”

At town halls with riders, RTD has pitched a plan B, one that would see a B Line train from Denver to Boulder and Longmont, but with only three services southbound in the morning and three return services northbound in the evening. A proposed partnership with BNSF Railway would let RTD use portions of their line, thus potentially shaving large amounts of time and money off the project’s construction.

“That’s the idea, so hopefully we can bring it sooner rather than later,” Stanley explained. “It’s obviously RTD’s goal to have a good, connected, safe, reliable network. And if this is part of that, that would be great.”

Another Plan B: Plan Bus

Bobby Dishell, Director for District D with RTD
Bobby Dishell, who represents District D on RTD's Board of Directors

There are others who argue we need to rethink our transit even more broadly, including Bobby Dishell who sits on the RTD Board of Directors. Given his title, it’s fair to say he is a supporter of public transit. Still, he wants to make sure riders, voters, and the planet are getting their money’s worth.

“Whether it’s $1.5 billion, or a half a billion dollars, is that amount of money really the best way to provide strong service to the entire region, including to that area?” Dishell asked of the B Line expansion. “A lot has changed since 2004. The population has changed dramatically.”

Dishell noted a stronger focus on environmentalism across the community since voters approved the B Line, and explained that much of the expanded line would likely be fueled by diesel and gas rather than electricity.

“$500 million — even if it’s an incredibly conservative estimate — is about 500 electric buses,” Dishell said. “Whether it’s autonomous vehicles, hydrogen vehicles — I think the future of transportation is exciting. I think it’s fascinating. I’m looking forward to what we’re able to find.”

There is an important follow-up question to an alternative proposal, such as a new fleet of buses: Is a non-train alternative even an option legally speaking, since Colorado voters specifically approved a train? RTD told Denver7 it views that as unclear, and as something that would need to be discussed and explored if the decision is made to ditch the rails.

Bai’s still bussing

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Justin Bai rides an RTD bus

While community leaders and voters continue to discuss and debate the elusive B Line expansion, Justin Bai continues to rely on his weekly bus rides to make it to work and class. While other drivers sit idling in standstill traffic on I-25 and US-36, he gets ahead on his work and catches up on his favorite podcasts, all while his commute is done for him.

“It takes me about 40 to 45 minutes to get from Denver to campus in Boulder,” he said. “It’s nice to have some time where I can relax and just read, or just space out if I need to.”

Bai is still squarely on Team B Line, but he’s Team Bus, too. He views the two as complimentary, not competing, visions. His ultimate goal is to get more of his fellow Coloradans into a broader coalition, one that is pro-public transportation across the board.

“I’m hoping the future of transportation is one where public transportation is really accessible and looked favorably upon,” he said. “I’m hoping that buses and trains, as well as walking, rolling, and biking are given the love and appreciation that they need.”

Your B Line Take

If you have thoughts on the future of the B Line, both Denver7 and RTD want to hear from you. You can learn more about RTD’s Northwest Rail Peak Study on its website. We’re told the results of the study will be presented later this year. You can weigh in with Denver7 by emailing us at

'Quit trying to waffle out of what voters were promised!'

I was one of the many who voted in 2004 FOR a train line from Denver to Boulder. Many, like me, feel betrayed by RTD since we have seen lots of different train lines being built in the metro area, but nothing substantive in more than 19 years for the promised B line. It is likely I will be dead before (or if) the promised line is ever built. However, I STILL want and DEMAND that it be built: I say to RTD: "Quit trying to waffle out of what voters were promised! Make resources available to actually start building, even if this means other train lines are put on hold! We in the northwest corridor have seen ten of millions of dollars being spent on other lines in 20 years, and if those resources had been spent on the B line, it would long since have become a reality!"
Ronald C Antweiler

'I want my tax money back'

We were promised a train 20 years ago, and were sold a bill of goods. Not only did we not get a train, RTD has found money to expand their footprint in Denver without fulfilling their initial promise to Boulder and Longmont. I want my tax money back.
Mike Atkins

'Has anyone looked at a dedicated bus lane throughout the western slope? Improved bus economy or total electric buses?

'a great rider/tourist experience'

I have been saying for years to install cable cars. They don't need to be 20ft in tbe air either. Cable cars can run 6in off the ground. Towers and cable is a far easier install, clean electric energy and a great rider/tourist experience.
Doug Masser

'It's time to think beyond cars as the only way to travel'

Public transit can provide so many benefits to our entire community and metro. Reduced traffic, emissions, better health, affordability, etc. We need to prioritize it as much, if not more than, we do for cars. 1 in 107 Americans will die as a result of a vehicle crash. That's absolutely insane and would result in a public health emergency for anything else. Yet we continue to fund car infrastructure which is incredibly expensive both publicly and personally for every one of us. We need to build more destinations around our transit stations, including housing, grocery stores, gyms, offices, and entertainment. If we don't prioritize transit, we will find more of us and our loved ones in car crashes, suffering from asthma (tires create pollution too, so EVs don't solve this), and spending time isolated in our cars instead of with our community sharing transit. Car infrastructure, parking, highways, are an incredible waste and detrimental to our metros economy, air quality, social well-being, and health. It's time that we stop building parking lots, expanding highways, and building for cars instead of people. More of us will die, more of us will have asthma, and more of us will struggle with car payments. It's time to think beyond cars as the only way to travel, and seek alternatives that are beneficial for everyone.
Brian Holman

'I would like to know how much money has been collected'

As a resident of Longmont, I was very excited at the prospect of being able to hop a train to Denver and not bother with parking or traffic. It has now been 19 years since the voters approved the tax to build the project, but no train or even a plan-in 19 years! I would like to know how much money has been collected from the people in the Norther district, this should be easy to determine, and how many times the project has been studied. I am guessing that most of the collected money has been spent on the never-ending study or "loaned" to other light rail lines so they could be completed. Thank you for providing this format to voice our concerns.
Dennis Davisson

'Has anyone looked at a dedicated bus lane through the Western Slope?'

Do you remember when the A line stopped working? People had to walk a long way to get down to a bus to take them where they needed to go. I agree that we need to look at real solutions that gives more for our money and a rail line is not it. Has anyone looked at a dedicated bus lane throughout the western slope? Improved bus economy or total electric buses? When the bus breaks down another one can come and continue on its route. What a train breaks down, a Bus Has to do it. I can imagine the freight line, throwing a fit, the first time one of our passenger trains break down and halter transportation for hours.

Editor's Note: Denver7 360 | In-Depth explores multiple sides of the topics that matter most to Coloradans, bringing in different perspectives so you can make up your own mind about the issues. To comment on this or other 360 In-Depth stories, email us at or use this form. See more 360 | In-Depth stories here.