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Oct 17, 2011
Engineering

Why is Boarding and Alighting an Urban Gondola Seen as a Problem?

Post by admin

Like Escalators and Moving Sidewalks, Urban Gondolas also involve boarding and alighting a moving "vehicle." Image by flickr user JD Lasica.

Perhaps the oddest argument against Urban Gondolas is the boarding and alighting process. Oftentimes, people complain that passengers will be unable to board and alight these systems given the unique process involved:

Generally speaking, urban gondolas move through stations at what is known as “crawl” or “creep” speed. While crawl speed can vary by system, a good back-of-the-envelope rule is 0.25 m/s or 0.9 km/hr.

Some might consider that fast. Others might notice it’s significantly slower than the average speed of escalators (0.30 – 0.61 m/s) or moving sidewalks (0.5 m/s) – two technologies where boarding and alighting also occurs while the method of conveyance is in motion.

It’s also worth pointing-out that these technologies are also used constantly by both the disabled and able-bodied alike?

So what gives?

My gut says there are four things at work here:

Firstly, when boarding and alighting an escalator or moving sidewalk, one is moving in the same parallel direction as the method of conveyance. In a gondola situation, one is moving perpedicular to the method of conveyance. Whether this has an impact on one’s ability to board or alight is unclear, but it likely causes a difference in perception.

Secondly, the wheelchair-bound are not often (if ever) be seen riding escalators and moving sidewalks. This may create the impression that any method of conveyance that moves during the act of boarding and alighting is therefore inappropriate for the disabled or elderly.

(Note: Boarding and alighting for the wheelchair-bound is common and simple. Please see moments 1:10 – 1:30 of the Rostock Gondola video for evidence.)

Thirdly, it is not commonly known that most gondola systems are equipped with a manual override mechanism that allows a station attendant to routinely stop the vehicle mid-station to ease boarding and alighting where necessary. Furthermore, systems such as the Bolzano 3S come to a complete stop in stations while the Sulphur Mountain Gondola in Banff is moved through stations by hand thereby allowing for full-stop boarding and alighting.

Lastly, for reasons only a cognitive psychologist could explain, new ideas are always held to a higher standard than older ones. It’s the same reason people question how well a gondola performs in the snow yet never ask that same question about light rail or streetcars.

People are funny that way.

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10 Comments

  • GiorgioXT says:

    Its technically and not difficult to have a complete stop , it means just to have more cabins into the station , and indeed, early 2-places or 4-places gondola worked this way, with cabins loaded when stopped and then manually pushed on line.
    The passage to slow-moving arrived with the automation, but also as a consequence that people , particularly arriving, didn’t want to wait the complete stop… showing by fact that it wasn’t a problem.

    However, its already feasible to have a “fast” line of cabins and a “slow” line in station or to insert a “special” cabin loaded at full stop – some MGD have already -thanks to high-speed switches- the possibility of having cabs that stops at intermediates stations or go directly to endstation.

  • jules says:

    Here’s a potentially over complicated idea:

    Why could you not create a moving sidewalk boarding/exiting platform? That way the rider is already moving at the same speed and same direction as the gondola cabins (or platform, for alighting). In fact, you could potentially then speed both moving platform and cabins up, and decrease station dwell times, while simulating a “complete stop” boarding or alighting scenario. Of course you would have to step on or off the platform in the station, but this could be done in the direction of travel, similar to a moving sidewalk or escalator.

    • Interesting idea Jules. I can see this working at intermediate stations due to the often straightish line orientation, but the line orientation for end stations is curved. I don’t know how you would get around this aspect – I have never seen a curve in a moving sidewalk.
      Another benefit not mentioned is you could increase the acceleration distance and bring cabins on to a faster line speeds (without crazy G’s) and maybe, just maybe, even reduce the length dimension required for stations? Hmmmmmm.

      • jules says:

        The end stations are curved, it’s true, but there are straight sections of track at the beginning and end of the curve, so i’m imagining that would be where this could work — one moving straight part for exiting, right when the cabins enters the station, and one moving straight part for boarding the cabin, somewhere after the center point of the curve.

      • Matt the Engineer says:

        Just use a spinning disk for the end stations, and a platform that enters tangentially (you don’t walk from outside the circle toward the middle, but instead in the same direction as the spin).

        • Steven Dale says:

          I think the question is this: Are we trying to overcomplicate this? The technology works as is and I find it pretty hard to imagine how moving walkways in the station would improve the situation.

  • Moving sidewalks are a fascinating idea! I tried to construct it (first results you can see on my website, but only in German language).

    The problems are:
    o How do you step on the rotating platform? You need a staircase and an elevator leading to the small center of the platform.

    o You need space for arriving passengers and for departing passengers, so the platform needs a bigger diameter, so you need more space for the station, the gondolas have to drive a longer circumference, you need more time at the intermediate stations, your cruise speed increases, you need more energy,…

    I believe, it is more easy to stop every third gondola for handicapped persons at a different track/sidewalk.

    Or you step in/out on the inside of the turn not at the outside.

  • GiorgioXT says:

    Curved conveyors are not a problem , like airport baggage retrieval show ; but it isn’t really indispensable , just have a slightly longer station – however shorter than a LRT or Tram stop , a fifth of a metro one- and you could have either a straight conveyor for loading/unloading or a section where tha cabina are a full stop for 25″-35″

  • sari says:

    When I think about the major impediment to installing cable cars in our country (Israel), it seems to be their vulnerability to terror attacks. During the intifada people in Israel stopped riding buses because so many were the targets of suicide bombers. Dangling high in the air in a glass box knowing that the cable holding me up could be easily bombed or shot by someone hiding on the street or the rooftops does not make me feel very secure. This is not a problem for most Western countries, but is the sad reality in many places in the Mid East and Asia.

    • Steven Dale says:

      Sari,

      I totally understand and sympathize with your perspective. My response is twofold:

      a) Is the threat of terrorism any more or less than any other form of transportation? In the last ten years we’ve seen airplanes, buses, subways and (I think, though I could be wrong) trains as targets of terrorism.

      b) I heard a story that for security reasons Hugo Chavez had the Metrocable cabin he rode in during its launch in Caracas equipped with a bulletproof liner. That might be a solution to the problem you describe.

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