Posts Tagged: Engineering



How the London Emirates Air Line Cable Car Powers its Cabins

The issue of energy has come up a lot when we talk about urban cable systems — and for a good reason. If cable is going to succeed as the modern, comfortable, city transit technology it claims to be, then such amenities as heating, air conditioning, video screens, wifi, and two-way communication systems are going to have to be standard features.

For most of their existence, gondola were not heated, cooled, or souped-up in any way because frankly, there was no need. If you’re skiing outside all day you don’t exactly want to step into air conditioning and heating is not necessary since you’re all bundled up and only inside for a few minutes at a time. But as cable moves into the urban realm, the issue of power becomes increasingly more significant.

Can cabins be heated and cooled?

Yes. For example, London’s new Emirates Air Line cable car has air conditioning. In fact, we’ve know that it was possible for a while, having had this discussion before, we just weren’t sure how.

The solar panel is not the answer

So how do cabins get power?

First off, definitely not from the small solar panels seen on the roof of some gondolas. Since gondola cabins aren’t connected to a power source, heating and cooling, etc, is not as straight forward as say, in a subway. But this doesn’t mean it can’t be done.

Last week an article came out about how the Emirates Air Line cable car in London utilizes ultracapacitors to provide power to each cabin. So there we go, voilá.

Each cabin has an ultracapacitor on the roof

But what does that mean and how does it work?

Ultracapacitors are like batteries in the sense that they both store energy. A capacitor, on the other hand, unlike a battery, can charge and discharge energy very, very quickly (like in a matter of seconds). In the case of the London gondola cabins,

“48V ultracapacitor modules fitted on top of each car [to] enable split-second, rapid energy charging of the modules on reaching the charging stations located at both turnaround points.”

Maxwell Technologies 48 V Ultra cap

Capacitors have a longer lifespan so you can repeat this process way more than with a battery — in this case, up to one million charge/discharge cycles — and they require little to no maintenance.

The rapid charge is key because it means that the capacitors can charge as the cabins pass through stations. A battery, on the other hand, would need a much longer charge period. Since the capacitor is continually charged through out the day, its physical size can be reduced. For a comparable battery system that would recharged at night, the sheer amount of batteries needed for each cabin would probably be far too heavy and too costly to be practical.

The ultracapacitors installed in the Emirates Air Line cable car were manufactured by Maxwell Technologies. The capacitors are a green technology that use electric fields, rather than chemical reactions, to store energy. The Maxwell 48V modules are the same capacitors used in hybrid buses and construction equipment. They can allow for high bursts of power needed to accelerate or to lift a heavy load (opposed to a gradual loss cruising or lowering a load) and they can quickly recapture energy from braking.

In conclusion, yes, gondolas/cable cars/aerial cable transit cabins can be individually supplied with enough energy to power temperature regulators, multi-media screens, and all the lighting necessary for your ultra-comfortable, ultra-modern, and ultra-fun cable experience. You just need to add ultracapacitors to the top of each cabin to charge everything up in the station and you’re good to go.

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Elevated Beauty

Chicago's 'L' elevated subway system is one of the most well-known elevated subway systems in the western world. Image by clarkmaxwell.

Elevated roadways, busways, light rail lines, subways, automated people movers and cable cars are far cheaper to build than underground systems. They’re not as cost-effective as street-level systems, but street level systems are subject to all the whims and unpredictability of intermingling with other forms of traffic.

Problem is, most architects, urban designers and politicians will complain about elevated systems as an eyesore; detrimental to the urban fabric. It’s an argument that has little merit, least of all because they have so little evidence of it.

They’ve seen how ugly, elevated infrastructure can abuse a neighborhood and have decided (yes, decided) that all forms of elevated infrastructure are ugly and abusive. It demonstrates just how little imagination and creativity our existing planning regimes possess.

Just because most elevated infrastructure is ugly doesn’t mean it must be ugly. At worst, ugly is a choice. At best, ugly is an opportunity to be beautiful.

An ancient Roman Aqueduct in Segovia, Spain. Image by Éole.

See what I mean?

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Cable Splicing

Last week’s post about six common uses for steel cables generated significant conversation and questions about the cables themselves. One question that was not asked, however, was how a company goes about splicing the two ends of a cable into one continuous loop.

I’m told this is one of the most impressive aspects of a cable system’s installation and is something I, myself have never witnessed. Only a handful of people worldwide are licensed to do this incredibly specialized operation. This multi-day operation involves a team of individuals untwisting tens of metres of steel cable and then re-twisting the two ends together at regular intervals in order to complete one single complete loop.

It is also this section of cable that is the most vulnerable to damage, thus the specialized nature of the operation.

For a great insight into this, check out Lift Wold’s cable splicing photo essay to see a cable splice, step-by-step.

Pretty impressive stuff.

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The Spindle

My mother owns a loom she uses for making small blankets and an occasional wall hanging. When I was four she pulled me away from my blocks and legos to hold a spindle of yarn while she unrolled the thread and rewound it into a ball. For several minutes I did as I was told, until a better solution occurred to me. I asked my mother to cut a piece of string, which I slipped through the hollow core of the spindle. I tied either end to the edge of a tall metal basket. The spindle could now twirl freely on its own, and I could return to my blocks.

. . . Search for simple, elegant solutions to ordinary problems – and some not so ordinary. Why settle for what’s given when finding your own superior solution is just as possible?

Thanks so much to Julia Padvoiskis for allowing me to use her story. I couldn’t agree with her more.

We need more people who think like Julia.

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Foresight & The Bloor Street Viaduct

Construction of Toronto's Bloor Street Viaduct in 1917. Public Domain image from the Toronto Archives

Toronto’s Prince Edward Viaduct (most commonly known as the ‘Bloor Street Viaduct’) is one of my favorite pieces of infrastructure in all of my hometown.

This 1918 Art Deco masterpiece was the cornerstone of the city’s plans to connect the growing metropolis with disconnected suburbs across the Don Valley River system.

Is it functional? Yes. Is it beautiful? Absolutely. Most importantly, it’s one of the best examples of transit planning foresight I can think of.

Read more

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Forcing Functions

We all do stupid things. Constantly. Wouldn’t it be nice to have something that prevents those things?

Forcing Functions are a principle of industrial and interactive design that shapes human behavior in order to prevent error when using a machine, interface or system. They are functions that – quite literally – force us to behave in a particular way. Forcing Functions are often irritating and annoying but when designed properly, they prevent behaviors that are even more inconvenient and irritating:

  • The reverse key lock in cars. Before the advent of the key lock fob, cars could not be locked from the inside. Was it inconvenient to have to lock the car manually from the outside? Yes. Did it prevent thousands of people from locking their keys inside their cars? Also yes.
  • Placing your alarm clock out of reach of your bed. Yes, when the alarm goes off you have to get out of bed to turn it off. Really irritating, especially on a cold winter’s morning. But more irritating is when you slap the alarm off half asleep and miss your 8 am conference call.
  • Keycard activated lights in hotel rooms. Lights will only be engaged once you insert your hotel keycard in the appropriate slot. Prevents people from forgetting their card and from leaving lights on. A great example of a Forcing Function that benefits the service provider rather than the user.
  • Child proof medicine bottles. One of the most benign and irritating Forcing Functions ever developed. But the display of strength and ingenuity needed to open these bottles prevents children from accidentally ingesting medicine they shouldn’t.
  • Freezing your credit card in ice. A classic from the debt-reduction self-help world that is rarely if ever seen as a Forcing Function. The time it takes to return home from the store and thaw out the credit card provides room to pause and contemplate, preventing poorly thought out impulse purchases.
  • Repeated requests for confirmation of a computer-related action. 99 out of every 100 times you know you want to delete the file you just asked the computer to delete. So why then does your computer keep asking you if you’re sure? Because there’s always that one time out of every 100 when you’re not sure.

Forcing Functions are all around and often completely invisible to us. And yet they seem noticeably absent from our existing transit systems and technologies. I can think of at least half a dozen problems with public transit that could easily be resolved with the proper Forcing Functions:

  • People who do not exit by the rear doors of transit vehicles.
  • Riders who dangerously rush down stairs and platforms to “catch” a departing vehicle.
  • People who refuse to let people off of a vehicle before they board.
  • Drivers who take unapproved breaks.
  • Not having the “exact change.”
  • Riders who will not move to the ends of a subway platform or to the back of the bus.
  • People on escalators who clog both the “walk” lane and the “stand” lane.
  • Chronically behind-of or ahead-of schedule vehicles.

As I see it, our current transit systems are not designed to recognize how people behave in reality. They are instead designed under the assumption that people are purely rational decision-makers that will behave as they are supposed to. We know, of course, that this just isn’t the case.

I suspect there’s something in the human condition that doesn’t like the concept of Forcing Functions because it implies that we are fallible and capable of moronic errors in judgement. We don’t like to think of ourselves as stupid and therefore don’t like the idea of a system forced upon us to correct for our stupidity. No one likes to be reminded of their shortcomings, after all.

Problem is we are stupid. Each and every one of us. And there’s nothing wrong with that, so long as our stupid decisions don’t ripple through an entire system to the inconvenience and hassle of thousands. Why not just admit that, design around it and move on with our lives?

Ironically, admitting to our own stupidity might just be the smartest thing we could ever do.

Beyond those listed above, what other public transit problems can you think of that come down to simple, stupid human error? Name a few and try to suggest a simple Forcing Function that could correct for it.

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The Wuppertal Schwebebahn

The Wuppertal Schwebebahn in Central Germany. Image by JuergenG.

In the central German city of Wuppertal is a piece of transit infrastructure completely unique in the world.

Translated directly, the Wuppertal Schwebebahn means “floating railway” and it’s easy to see how it received it’s name. Built in 1900, the Shwebebahn in the oldest monorail on the planet and an elegant piece of transit history and infrastructure. (FYI – It’s not cable propelled.)

Even 110 years ago, civil engineers understood the problems of public transit co-mingling with other private modes of transportation. But unlike today where we try and work around the problem of mixed traffic with dubious Transit Signal Priority Schemes, these engineers decided to forget about the band-aid approach and just get out of traffic’s way completely. And in doing so, they arrived upon the solution of creating the world’s first “hanging monorail.”

While the age of the system gives its infrastructure considerable heft, it’s not at the expense of the urban environment. The green support structures arch gracefully and their conspicuously large steel rivets conjure images of turn-of-the-century skyscrapers and the Eiffel Tower.

Much of the Wuppertal’s route lies overtop of the local river. Whereas some might have thought such a scheme would only be useful for crossing rivers, Wuppertal planners were wise in recognizing the other more intrinsic value of river corridors: Running along a river instead of across a river opens up wide areas of public space and provides an attractive view for riders.

The Wuppertal Schwebebahn shows how aerial transit systems are not only possible, but elegant, practical, safe and efficient. The Schwebebahn has an excellent safety record, and is still an essential part of that city’s transit infrastructure; not just a toy for tourists. It also suggests how an aerial gondola system might be similarly configured/integrated into the urban environment.

Check it out:

Special thanks to Christian for suggesting I discuss this unique and amazing system.

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