Introducing “Stacking” or The Dual MDG

Post by Steven Dale

Yesterday I asked people to consider the implications of two images of relatively obscure gondola transit systems, the Madrid Teleferico and that Ocean Park Gondola.

These systems reinforce the idea that “stacking” or “doubling” of a gondola line is possible. The implications are the very same I outlined in a previous post about the Sugarloaf Double Double Chairlift. There is, however, a big difference here.

When I discussed the Sugarloaf Double Double, I said this:

And yet here in Sugarloaf we have a system from the 1970′s that demonstrates that the concept is not so outlandish. It suggests that there is actually an historical precedent for such an idea.

Now of course a double-seater chairlift is a different beast than a gondola system. Nevertheless, it doesn’t take much of a mental leap to move from two loops of chairlifts on the same tower to two loops of gondolas on the same tower. The concept is equivalent in spirit if not exactly in execution.

The Ocean Park Gondola. Image by flickr user Luke Chan.

The Marid Teleferico. Image by flickr user R.Duran.

In the Ocean Park situation, we can clearly see two different sets of towers carrying two different loops of gondolas. The key, of course, being that they are moving through the same corridor.

This means increased capacity, decreased wait times and the potential for express lines and skip stops.

They don’t, however, share the same tower infrastructure (though they presumably share the same stations).

So while the concept of stacking is displayed in principal, it’s not demonstrated exactly in execution.

When we look at the Madrid Teleferico, meanwhile, we’re left with a somewhat more puzzling situation. In this situation we don’t see two lines of gondolas. We do, however, see a tower that has clearly been constructed to carry a second line. Were there a second line in operation, we would again witness increased capacity, decreased wait times and the potential for express lines and skip stops.

And while the holy grail here would be to see two lines in operation on the Madrid Teleferico, seeing only one is also an opportunity: The Madrid Teleferico demonstrates how a line can be designed with the intention of doubling capacity in the future, without necessarily committing to it in the present.

The funny part about these two systems is that we here at CUP have known about them for a long time. We’d seen pictures (even used one here) of the system, but had always sort of dismissed them as mere Toys for Tourists. We didn’t discover the stacking implications until just a couple of days ago. We’d never seen the right picture of the right piece of infrastructure from the right angle.

It’s quite amazing really. The more you learn about something, the more you learn how little you really know.

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  1. Due to reading this post and yesterday's, it occurred to me that having the cable loop where the main part of the loop is parallel with itself (ie an up and a down) and sharing the same tower is not the only configuration. There could be circular, or irregular, or even figure-8 patterns. Then there could be more stations that are not linear (or linear with a bend), but placed just about anywhere they are needed. I wonder are there any extant examples?
  2. Hi Matt, I couldn't understand that. Could you make an easy sketch or use Microsoft Paint to explain? Would really like to understand. :)
  3. @ LX, I know what he's saying. Basically could you have a single loop that goes in one direction? In which case, you could turn corners.
  4. @ Matt T, You're totally right. This is a topic I've been meaning to write about (if I understand you correctly). Such systems have already been built in the past. What you describe could basically provide for on-tower turns.
  5. @Steven Sorry, still don't get it. It doesn't make any difference if it is one loop in a circle or the common way.
  6. LX, You have to imagine to separate loops both in a circular configuration; one moving clockwise, the other moving counter clock-wise. In that situation, you can accomplish on-tower turns in both directions. The problem with on tower turns isn't the turn itself. The problem is accommodating the turns of both lines. In the Rostock BUGA system (if I'm remember) they were able to accomplish on-tower turns, but that's because the system was uni-directional. Does any of that make sense?
  7. I can imagine the loops. (They are practically not different from a common system). Corners will remain corners. Doesn't matter if on the inside of the circle or outside. http://oi56.tinypic.com/zkn0wj.jpg It would be good to have just one of those loops for Spokane (because going the same way back you came is a bit boring (just one station).
  8. I actually meant a single loop opened out. On the left of the picture is a traditional layout of an aerial gondola, as going up a dozen hills. On the right is what I meant: http://i55.tinypic.com/b3phn4.jpg So with a single loop making a large circle it can service lots of stations. Throughput and pph are lower, but it might suit certain locations. There's no need to have another cable moving in the other direction. "The problem is accommodating the turns of both lines. " - well that problem would go away. And my original comment as well as being cryptic, was probably off topic for this post, kind of.
  9. Yes, imagine that track about 5 km long. You want to go from station B to station A. Take a ride over C, D, E to get from B to A. This will take you about 20 minutes - with a fast working system. In that design (the picture), the corner-turns are outside the station. Is that right? All turns are just next to a station, so I'd suggest to put them into the station. The problem with the turns on towers remain, whether it's inside the loop or outside. The corner must be very large for a smooth passing or have break and acceleration technology, so the size can be minimized to the size of about a small station. A mix of both probably would be the best solution. Or you have the corners where you could use them for something else: low speed = entering of passengers -> inside a station. It sort of reminds me of the Pittsburgh Gondola: http://maps.google.com/maps/ms?ie=UTF8&hl=en&msa=0&msid=112539388608142218651.0004890703b3f7a17fe19&z=13 Those lines should definately be closed to a loop (blue line to itself or blue to red. Now here's the good thing: Using the system you suggest twice (one way and another) there is a major advantage: if one way fails to move, you could use the other direction to get to your destination (see the sketch I posted). If you have on or two common lines like I suggest on graph 3, there will be a non-working gap within the line. =) Again: problems with turns and corners remain.

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