Posts Tagged: Corners

17
Sep

2012

This Week’s Tweak — The Corners Page

In an effort to continually improve and expand the offerings on The Gondola Project, each week we’re rolling out a “tweak” to the site. If there’s a part of the website you’d like to see “tweaked” send us an email at gondola (at) creativeurbanprojects (dot) com.

This week we’ve update the corners page. It now features information drawn from various posts about systems and turning methods we’ve discovered including turning at towers vs turning at stations, what technologies can turn corners, and why this is important.

You can get to the page from the Learn the Basics page, under Learn About Cable Transit in the header or by clicking here.



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10
Sep

2012

This Week’s Tweak — Learn About Cable Updates

In an effort to continually improve and expand the offerings on The Gondola Project, each week we’re rolling out a “tweak” to the site. If there’s a part of the website you’d like to see “tweaked” send us an email at gondola (at) creativeurbanprojects (dot) com.

This week several changes were made to the Learn the Basics section, found under Learn About Cable Transit in the header bar. New information on Cornering and Towers has been added to the Learn page — with a collection of related posts on the individual pages. Since there are a ton of posts (over 1,000) on the Gondola Project, sometimes it is hard to sort through what is there, and that is why tweaks are here — to gather up and start sorting through all the bits of knowledge we’ve collected thus far.



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14
Nov

2011

Cornering Gondolas In Squaw Valley

Ted wonders how a former Pulsed Gondola at Squaw Valley (seen here) manages to turn in both directions. Image via Skilifts.org.

Ted writes:

I wanted to tip you off to something I stumbled across the other day– you may already know about it, but on the off chance you don’t, I thought it was worth bringing up.

It seems Squaw Valley ski resort has (or actually, had — it got taken out this summer which is why i heard about it) a pulsed gondola that has a mid-path turn. The odd bit is that it seems it is NOT a detachable lift, but still manages to make a significant turn (looks like 20 degrees or so). I assume since it is pulsed that it slows down at the turn… but still I cant understand how this works. I’ve never heard of a lift that could turn in both directions without detaching.

I hope this helps you in some way (and id love to see a post on how the heck this is possible… it makes my head hurt trying to think about it).

Firstly, I want to say thanks to Ted for sending this along. I’m not sure we’ve ever encountered anything like this on The Gondola Project, and it’s well worth exploring.

While I don’t know for certain how a system such as this works, here’s my guess:

As we discussed last week, gondolas can turn corners but must do so on the outside/convex side of the corner. This is because the vehicle grips grab onto the rope from the outside of the rope. That means while a gondola can tackle the outside of a corner in the (for example) inbound direction, for the outbound direction it would have to tackle the corner on the inside of the corner – which is not technically possible.

Currently the solution to this problem is to make the inbound and outbound directions of a system ply different routes than one another with every single corner being either a right hand turn (assuming a clockwise rotation) or left hand turn (assuming a counter-clockwise rotation).

The only other way of dealing with this problem is to somehow switch the grip configuration in-station such that in the outbound direction the grip is then attached to the inside of the rope loop. But from what we know, such a technology doesn’t currently exist (though it may).

But this only goes for detachable gondolas. As you pointed out, this is a Pulsed Gondola system. As such, the cabins are fixed to the line – and have the ability to shuttle back-and-forth along the rope loop rather than circulate around the rope loop. Such motion would not be unlike an Aerial Tram configuration:

A circulating system (top) versus a shuttle system (bottom). Note: This image is not depicting how the Squaw Valley gondola would work. It's merely to demonstrate how vehicles circulate through a system or shuttle back-and-forth in a system.

Now let’s assume that on one side, the gondola is fixed on the outside of the loop and on the other side the gondola is fixed to the rope on the inside of the loop. Should the vehicles always shuttle back-and-forth (rather than circulate around) in the system, the gondolas will always be on the outside of corners.

Makes sense?



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07
Nov

2011

The Kolmården Wildlife Park Cable Car, Sweden

The issue of turns and corners always seems to pique people’s interest, so consider then Sweden’s Kolmården Wildlife Park Cable Car.

Opened just recently, this 2.6 km long system transports 1,360 pphpd and includes a whopping 6 turns (5 if you don’t include the main station)! Take a look:




This is a fascinating system because it creates as many questions as it answers:

Firstly, the system is incredibly slow with a top speed of just over 6 km/hr. That’s fine for a zoo/resort setting (such as this system is), but would be inappropriate for an urban setting. My industry sources have informed me that a higher speed with such cornering would be possible, but would come at additional cost.

What that cost is and what that top speed would be is uncertain.

Stylized route plan for the Kolmården Cable Car. Notice how each and every turn is to the right. Image via Doppelmayr.

Secondly. While the system has 5 (or 6) turns, notice that each and every one of them is a right hand turn. This is due to the uni-directional flow of traffic – in this case counter-clockwise.

The basic rule of turning without intermediary stations is this:

Vehicles can only flow in one direction and all turns must be either to the left (in the event of a clockwise traffic flow) or right (in the even of a counter-clockwise traffic flow).

This makes sense as the sideways grip that characterizes detachable gondolas would prevent bi-directional traffic flows. (As the gondola’s arm must always travel on the convex side of a corner.)

However note the slim profile of the towers (1:00). Would it be possible to “stack” a second line on top of (or beside?) the first with vehicles travelling in the opposite direction, and therefore turning in the opposite direction?

My sources have indicated that, yes, such a configuration would be possible – again, with additional cost. In effect, to make such a configuration work, one would have to double the bull wheel and engine infrastructure and some of the line infrastructure – almost doubling the cost of the initial line.

But as this system uses simple and relatively inexpensive off-the-shelf MDG technology, one could argue that the increase in cost might be marginal compared to the other alternatives – especially given the resulting increase in service.

Engineers? You’ve got an opinion, I’m sure. Go for it.

 



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14
Jul

2010

Sydney, Absurdity & Queues

Colin writes:

I’ve been following your blog for a little while, and although my immediate impression was that the idea was absurd, that quickly morphed into “well why why hell not?”

I’ve been a skiier/snowboarder for almost 35 years, and have ridden a lot of gondolas. One question I have is to do with queue control. I’ve found that unless there is a dedicated and authoritarian staff member controlling the queue, groups of friends are reluctant to be split into separate cars, and, to a lesser extent, strangers are reluctant to ride together.

What tends to happen is that the majority of cars leave the station less than full, and that this occurs even when there is a lengthy queue. In fact it’s much of the reason for the lengthy queue in the first place. It seems reasonable for friends to travel together – a journey together is often part of the goal, and not just a utilitarian way to arrive at a destination. How is this problem solved in urban transport gondola systems like in South America?

Also, I note that the gondolas can turn corners only with the help of a large (and expensive) turning station – otherwise they have to run in a straight line. When I look at my home city (Sydney, Australia) I note that almost no roads run in straight lines – they’re all curves, bends and corners. Combined with your advice to never put gondolas over private property, it seems the opportunities for gondolas in Sydney would be very limited.

There’s two parts to your email, Colin, but before I get to them first let me begin by thanking you for being open-minded enough to move from the absurd to the “why the hell not” position. I think everyone who first encounters the idea goes through a similar process of de-bugging. I also think it’s just plain easier for skiers to wrap their minds around.

As for queue-control, you’re totally right. Station attendants are a complete prerequisite. During rush hours, people wouldn’t be allowed to ride separately, vehicles need to depart at capacity. Though it would be wise to implement a dual queue strategy such that women could ride in female-only cabins should they desire.

Interestingly, Medellin implements a rush-hour dual queue strategy for a different reason: If you want a seat, you wait in the long line. If you don’t mind standing, you wait in the short line. It works well. But as I’ve mentioned before, the original Medellin Metrocable line suffers from over-crowding during rush hours and they’re planning a second parallel line to relieve congestion.

During off-peak hours, congestion and queues aren’t a problem and a vehicle is no more than a few seconds away.

Strangely, Medellin actually implements a policy whereby a vehicle cannot depart with only one person in it. This is meant to increase safety and decrease vandalism. It seems counter-intuitive, but they’ve found it works well. I’m not sure how well such an idea would fly in an English-speaking country.

As for Sydney: I don’t know, Colin, I’ve never been there. Currently cable systems do require angle stations to execute turns. However, they don’t have to be as large and imposing as you think (the Grindelwald-First is a great example of a slim-profile turning station).

I think that Sydney is so carved up by waterways that cable might lend itself beautifully to the city in point-to-point water-crossings. But again, I don’t know.

One of the goals of The Gondola Project was to help people understand that cable is just one of many options. In fact, I hope people understand that when considering any technology. Cable isn’t a cure-all but neither is LRT, BRT or PRT. Maybe cable isn’t right for Sydney, maybe it is, I don’t know. I think it more important to empower people to consider this technology in their own backyards and on their own terms.

It would be impossible for me (or anyone else) to know everything about every city. Instead I hope the information in this site is used by people like yourself to imagine unique and creative ways to use the technology in their own hometowns. That way, everybody wins.

So maybe I should turn your question around: How would you use cable in Sydney?



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