It’s time for a trolleybus comeback

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Trolleybus in Seattle.

Trolleybuses are rubber-wheeled buses that are powered by overhead wires. They offer a number of advantages over regular buses, but are very rare in the United States.

There are currently only five US cities that operate trolleybuses. They are Boston, Philadelphia, San Francisco, Seattle, and Dayton. Trolleybuses are so rare because they require overhead wires, which are expensive to install, limit bus route flexibility, and are often considered ugly.

On the other hand, compared to normal diesel buses, trolleybuses are quieter, smoother, cleaner, and accelerate faster. They also offer a sense of permanence that normal buses can’t match.

Many of the advantages of trolleybuses come from their power source. Since they run on electricity rather than fossil fuels they emit no fumes, and they accelerate quickly, smoothly, and quietly. However, all those advantages can be duplicated by wire-free electric buses without the cost or trouble of overhead wires.

So why bother with wires?

Because the cost and relative rarity of wires is a sure signal that a transit route will be predictable and permanent. Wires provide the same sort of visual fortification that rail tracks provide. They are a clear signal to riders that they are dealing with a significant and special transit line.

Since so few trolleybuses have been built in recent years, and all the cities that use them have used them for decades, it is difficult to know how much of an effect wires without tracks can have on transit oriented development. Given the push for affordable BRT in many cities, the potential prospect of TOD-inducing buses is something that ought to be explored.

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Trolleybuses can shift lanes without disconnecting their wires.

Trolleybuses even offer a significant advantage over rail streetcars. Since they aren’t tied to tracks, flexible trolley poles allow buses to switch lanes in order to go around obstructions. Without tracks to constrain them, trolleybuses mixing in a lane with cars are less likely to be held up by traffic. Additionally, many trolleybuses are built as hybrids and are capable of lowering their poles and running on batteries or fossil fuels as a backup.

It is unfortunate that the so few trolleybus systems survived the 20th Century. Most of them fell victim to the same transit death spiral that destroyed most American streetcar systems.

However, streetcars are enjoying a renaissance because contemporary planners have discovered they can be useful. It may be time for trolleybuses to enjoy a renaissance of their own.

By | 2011-11-14T09:59:55+00:00 November 14, 2011|Categories: Technology, Transit, Transportation|13 Comments


  1. Dave Barnes November 14, 2011 at 10:46 am

    “Since they run on electricity rather than fossil fuels they emit no fumes,”

    And, this magical electricity is generated how?
    Oh, I know. By burning coal and gas. Not all of it, just 70%.

    • Matt November 14, 2011 at 12:30 pm


      You’re absolutely right about the coal powering these buses – but you’re overlooking a pretty crucial aspect of this scenario. A single coal plant is just that, a single point of pollution. You’re replacing dozens, perhaps hundreds of points of pollution in diesel buses with a single point. If coal somehow ever gets clean (yeah, right) or we can bring more renewable energy on-line, you’re still looking a single point of pollution versus the diesel engines powering all our buses.

      I could see this working on the 0 and 15 routes extremely well. Both are fixed-point routes through heavily congested corridors and neither is going to be moving anytime soon. Imagine if we could get some hybrid buses that would charge on the overhead electricity while on the most dense part of the route and swap over to battery/diesel while on the more far-flung parts of the route. For example, the 15 could run on electricity along Colfax between the Federal Center and Colorado Blvd and finish the run to Anschutz Medical on battery with a diesel backup. Or the 0 could run on overhead electricity headed south until the I-25 interchange and then switch over to hybrid technology.

    • Larry November 16, 2011 at 12:53 pm

      “Since they run on electricity rather than fossil fuels they emit no fumes,”

      I think the author was referring to the local power source for the vehicle rather than the source of origination. Generally, people do understand that most electricity is generated by fossil fuels. However electricity does have the potential to be much cleaner if the transit agency purchased all its energy from wind, or if it is in the Pacific Northwest where a huge percentage of electricity comes from hydroelectric and nuclear sources.

      This article brings up another advantage of electric vehicles. It shows that combustion engine vehicles generate a much greater amount of waste than do electric vehicles. I see no reason why the same would not be true of a vehicle powered by power lines rather than batteries.

      In addition, having the energy generated at a remote source rather than right next to me while idling at a stop light, just seems a little healthier – for everyone not living next to the power plant, of course.

  2. corey November 14, 2011 at 6:50 pm

    When I lived in San Francisco, the trolleybuses would get disconnected from the overhead wires all of the time. The driver would have to reconnect it, which isn’t always easy. Bratty kids would purposely pull on the cable on the back of the bus and disconnect the bus. Hopefully, the newer buses are better designed to eliminate this problem.

  3. MDB November 15, 2011 at 2:14 pm

    I was not impressed with the ones in Seattle. They frequently get disconnected and, should there be an accident or other cause for detour, you’re pretty much stuck waiting for it to clear up since you can’t go around.

    I’d also be curious to know how the Boston & Philadelphia systems handle major snow falls. The downed trees from the last two storms knocked out power on parts of S. Broadway for a couple hours, wouldn’t that also shut down the buses?

  4. Shane November 15, 2011 at 7:48 pm

    I moved up to Seattle from Denver in 2006 so have experience with both systems. I’m afraid the overhead-powered trolleybuses really don’t have much allure here – they certainly don’t have any more reliability than regular buses and as MDB said previously, they frequently disconnect when rounding corners. In order to avoid this, they corner much slower than a diesel-powered articulated bus and I think you would be hard pressed to find many Metro users who connect “trolley wires” with “predictable” or “significant.” We rarely get significant snow in the parts of the city with trolleybu service so I’m unsure how that might impact operations, but would be a bit surprised if overhead power presented an improvement.

    On the other hand, there has definitely been movement by the City to secure funding for trolleybus service expansion, so someone must see merit in them.

    • Dan Malouff November 16, 2011 at 8:49 am

      Seattle’s high per capita transit ridership and near total reliance on buses and trolleybuses is testament to them doing *something* right. Per capita ridership in Seattle is higher than Portland, and many of the busiest routes are trolleybuses.

      On other outlets where this article has appeared, it’s gotten a lot of “we love our trolleybuses” type comments from Seattleites. Not to suggest that is a universal opinion (of course it isn’t), but certainly it is true that a lot of people do like them very much.

      • Eric November 16, 2011 at 5:58 pm

        The main benefit in Seattle (where I lived until earlier this year) is that trolley busses are nearly silent when going up hills. For reference, Madison St. and Queen Anne Ave (both of which have all-day frequent bus service) have grades as steep as 19% ( ). On weekends when the trolley wires are being serviced, it’s really noticeable. This wouldn’t really be a benefit in Denver.

      • Shane December 13, 2011 at 7:17 pm

        Sorry, I guess I don’t see a correlation between the use of overhead power and user-perceived benefits such as reliability and extra significance with the line. Metro has the trolleybus intrastructure installed in areas conducive to it – a high density of potential ridership, frequent stops, and relatively high availability of overhead power. These are also factors that lend themselves to higher ridership, not the use of trolleybuses per se. Only 5 of the 14 trolleybus routes are counted among Metro’s “most productive” (riders per veh-hr). Now, the noise (or lack thereof) is an entirely separate issue and that is definitely a benefit on the exterior. I happen to find the trolleybuses a bit noisy on the inside but it’ a very distinctive noise and one I’ll forever associate fondly with Seattle…

  5. Keith November 16, 2011 at 8:03 am

    My father drove trolley buses in Seattle after WWII. He said that he could go 14′ left or right and still stay on the wire. Anything further resulted in a disconnect and then he tried to coast back under the wire so he could hook up again…

    Denver had trolley buses in the 1940’s and 50’s. Trolley buses went away when Denver went to one way streets in 1955 and didn’t want to redo the wires for the bus routes work on the one way streets…

    • Dave Barnes November 16, 2011 at 7:36 pm

      “1940′s and 50′s”
      I am sure you meant to write “1940s and 50s” as there is a shortage of apostrophes in the world.

  6. Justin November 24, 2011 at 9:44 am

    My understanding is that trolleybuses are particularly suited for cities with steep hills and abundant hydroelectric power. Electric motors have much more torque than gas engines, and as such can power up the steep hills of San Francisco and Seattle. Hydroelectric power makes up a significant portion of all power used in these two cities as well, although I’m not sure if that power is “cheaper” than other sources – maybe it once was. Anyway, I was told that these two factors made trolleybuses attractive enough to stay even when they were being done away with in other cities.

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