Posts Tagged: Dwell Times



Quick Dwell Times Demonstrated!

A gondola lift servicing Hasliberg, Switzerland includes a mid station (seen above) with only 40 second dwell times. Image via Remontees-Mecaniques.

Sometimes life is just weird.

Last week the issue of dwell times pretty much dominated conversation and discussion around these parts at The Gondola Project (here and then here). The main issue was whether or not dwell times were a real problem and if so, what solutions could be engineered.

And then – by some bizarre fluke – this past weekend I visited a mountain in the Berner Oberland region of Central Switzerland. That mountain, Hasliberg, happens to be serviced by a gondola lift that includes a mid station with dwell times of only 40 seconds (trust me, I timed it). That the station is so incredibly slim profile only heightens its importance.

A few caveats:

  • The top speed of this gondola is only 18 km/hr.
  • Vehicles can only carry 6 passengers.
  • System capacity is only 1,200 pphpd.
  • There is no major turn co-located within the station.

Increasing any of these metrics could, potentially, nullify the possibility of such short dwell times. Nevertheless, the Hasliberg gondola demonstrates that short dwell times are not just possible in theory, but demonstrable in practice as well.

Built by Garaventa in 1996, it bears a striking resemblance to the Grindelwald-First gondola -another major find in the Berner Oberland region of Central Switzerland. That system is one of the only lifts I know of that includes high-speed turns.

Combined, the Hasliberg and Grindelwald-First gondolas demonstrate that there is a whole sub-sector of cable tactics and technologies which are little known or understood. How these tactics are discovered and then usefully integrated into urban gondola transit systems will largely determine cable’s success into the future.

They also increasingly demonstrate the importance of our learning from existing ski resort systems as a means to improve upon existing urban systems.

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Are Dwell Times A Problem?

Are dwell times the real problem? Image by flickr user smatheson.

Sometimes we try to solve a problem because we were the first to spot the problem. Or we try to solve a problem simply because we want to solve the problem, not because it’s a problem that really needs solving. We all do it.

But trying to solve a problem no one has is a short trip to frustration and defeat. After all, no one likes to be told they have a problem – especially when they don’t seem to think what you seem to think is a problem. If you’re the only one that seems to the think the problem exists, maybe it isn’t a problem at all.

For example:

This week old post from last year on the subject of dwell times suddenly became the most commented upon post here at The Gondola Project. At issue was how to solve the issue of excessive station dwell times and off-line stationing.

In the post, I suggest that dwell times NEED to be reduced to make it a viable transit technology. The community concurred and a few brave souls set out to solve the issue. The discussion is long, involved and very engineering-specific. So engineering-specific I was kind of out of my element (as my lack of participation demonstrates).

Not to discount all the work and energy people put into this discussion, but to what end did they serve? Not too much, I suspect. Why? Because the cable industry does not believe they have a dwell time problem.

And they’re right. At least from their perspective.

From the industry’s perspective one needs dwell times of a minute or more because their paradigm is based upon a ski resort worldview. And when their attention shifts to the urban market, they see a paradigm that is barrio-based, topographically-challenged, economically depressed and centred on the developing world.

In the first situation (ski resorts), one needs long dwell times. In the second situation (developing world), the existing technology is more than sufficient to meet the needs of the market. Why, therefore, spend any more time, energy and money developing better technological solutions for the urban market? This is an especially apt line of reasoning when one understands that the urban market makes up a very small fraction of the cable industry’s revenues – roughly 10% of annual sales.

If you were in their shoes, you’d behave in much the same way. And if not, your shareholders would find someone who would.

Developments and innovations in a product need to match their setting – which is a factor of both time and place. Overshoot or undershoot in with either and you’ll likely miss the boat.

Do dwell times need to come down? Not in a 2 km long system in Medellin where – even with excruciatingly long dwell times – the system cuts residents’ travel times in half.

Move that system into North America or Europe, however, and then the situation changes. Suddenly the market is not characterized by winding, unplanned streets; extreme topographies; and few, if any, who can afford private transport.

Suddenly the market is about (reasonably) efficient traffic flows; families who can afford one, two or three cars at a time; and a culture of almost obscene impatience. In that setting and/or marketplace, dwell times do, indeed, need to come down.

But remember, the cable market is not centred on developed, western nations. It is centred on ski resorts and urban barrios in the developing world.

Oftentimes, it’s more important to develop the market before developing the innovation. If the market is screaming at the industry you must have shorter dwell times!!! you can be rest assured the industry will develop shorter dwell times.

Maybe we should spend less of our time trying to solve the problems the industry doesn’t have right now and more of our time spreading the idea into the markets we know will eventually result in the innovations and developments we dearly would like to see.

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Dwell Times

Image by Steven Dale.

True story:

While I was touring the Caracas Metrocable earlier this year, myself and my guide were joined by an elderly gentleman in our gondola. Via my guide, I asked the man how he felt about the system. Did he like it? Any complaints?

He said he loved it – except for all the time the gondolas spend in the stations.

When I looked back at my records, it appears that the man had a point. During my tour of the system, I recorded end-to-end travel times of apx. 14 minutes. 5 of those minutes were spent in the three intermediary stations, meaning more than a third of the trip is spent in stations. Dwell times were roughly 1.5 minutes at each station.

Dwell times are something the cable industry isn’t adept at handling yet and that needs to change. Based upon conversations I’ve had with cable engineers, the consensus is that dwell times can be reduced down to 20-30 seconds. Given that such dwell times have been observed in large detachable chairlifts around the world, there’s no reason to believe this isn’t true.

But for whatever reason, the industry tends to install systems with station dwell times of a minute or more.

This wasn’t something unique to Caracas, either. I witnessed similar dwell times with both the Medellin and Caracas Metrocables, suggesting this issue isn’t company specific (Poma built the Medellin system, Doppelmayr the Caracas system).

My guess is that dwell times are not something the cable industry has really actively dealt with in the past. After all, most ski lifts are point-to-point installations. Dwell times simply don’t factor into the equation on most ski hills.

Furthermore, in a ski lift situation, you probably would want dwell times of 1-2 minutes. Given all the equipment, gear and clothing skiers require, more time is needed to board and alight – especially when you consider how slow people move in ski boots.

But we’re not talking about ski hills here. We’re talking about transit and most commuters don’t wear ski boots.

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