Cable Misunderstandings on The Transport Politic

Post by Steven Dale

Yonah Freemak, the tireless creator of The Transport Politic yesterday wrote about The Gondola Project and a piece I wrote for Planetizen. Yonah takes the perspective that cable transit is an enjoyable, interesting technology and wades into the Form vs. Function debate I highlighted recently.

Yonah is an excellent writer, one whom I respect deeply. Yet while Yonah is generally positive on the concept, I have to point out one interpretive misstep and one factual misstep that he makes. First, Yonah’s interpretive misstep:

It’s true, of course, that it makes little sense to build a gondola in many cities — many places lack major elevation changes or large natural obstacles that preference an investment in a mode of transportation that simply goes over everything that’s around it.

I’ll be the first to admit that gondolas aren’t for every city, but I would never say that it makes little sense to build a gondola in “many cities.” Like so many, Freemark assumes that the technology is only appropriate for cities characterized by natural obstacles and or large elevation changes. Why? No reason is given.

I prefer to look at the technology as one that can exploit rather than just deal with natural obstacles. Rivers, valleys, parks and electricity corridors become usable space for transit that other technologies would not be able to utilize. This is a classic case of using what you have to your advantage.

Furthermore, Yonah misses the fact that traffic is an even greater obstacle in urban settings than “natural” obstacles. At least natural obstacles are static over time and space and can be planned for. No such luck with “unnatural” obstacles such as traffic, street protests, cyclists, and pedestrians. Worse still, standard transit technologies such as Buses, Streetcars and Light Rail only contribute further to traffic problems. Not so with cable systems.

Yonah’s second misstep comes when he says this:

There are of course major limitations to aerial vehicles like the gondolas Dale has highlighted; their maximum running speeds are relatively slow and they lack the ability to handle anywhere near the capacity of traditional train systems.

Two problems here:

Firstly, Yonah confuses “maximum running speed” with average speed. As I point out here and here, average running speed is all that really matters in an urban setting. Maximum speed is basically irrelevant. Just ask that guy in the Ferrari whose been stuck at 10 km/hr in dense rush hour traffic. Just because a vehicle is capable of operating at 100 km/hr doesn’t mean it will, which is why Light Rail vehicles today are built to a maximum speed specification well below what they were in the past. (Toronto Streetcars and Light Rail vehicles famously operate an average of around 13 km/hr but are built to operate at 100 km/hr).

Because cable transit systems operate outside of all other forms of traffic, vehicles are actually able to reach their maximum speeds. So while the maximum speed of a gondola may be less than the maximum speed of a streetcar or light rail vehicle or bus, it’s ability to operate outside of mixed traffic completely negates that. Yonah also completely ignores the issue of wait times, a stat with which cable has no peers (see  here and here).

Secondly, Yonah is right about one thing: Cable cannot approach the capacity of standard train systems. Here, however, I have to assume that he’s talking about commuter or heavy rail (subways). In that sense, yes, he’s right. But one of the things he misses is that few North American cities are building heavy rail systems because the capacity demands just aren’t there.

(Danish scholar Bent Flyberg, for example, has demonstrated that rail projects generally meet with ridership half of what was forecasted. This perspective is echoed by the US Department of Transportation and Harvard economist Don H. Pickrell.)

We therefore should be examining Light Rail and BRT capacities not Heavy Rail because Light Rail and BRT are currently what everyone is building. And when you look at the offered capacities of most Light Rail or Bus Rapid Transit systems in North America, rarely does one find a line that eclipses the 4,000 pphpd mark. Currently, aerial cable systems can reach up to 6,000 pphpd.

Like speed, we have a choice to build technologies that have a theoretical maximum capacity which we will never use or we can build a more modest technology that can easily provide what is required. If the two technologies were the same price, yes, go for the more robust one every time.

Problem is, LRT and BRT is anywhere from double to triple the price of cable on a per-rider-per-kilometer basis, (with far longer wait times and worse safety levels to boot.)

I duly appreciate the attention and generally favourable impression of cable Yonah’s article gives. I just think it important to recognize the deep-seated misunderstandings of the technology (in specific) and transit (in general) that exist (check out the Neumann-Bondada studies) and how those misunderstandings may preclude us from considering a truly revolutionary technology.

Remember: Cable Propelled Transit and Urban Gondolas aren’t just cool or interesting; they’re deeply simple and practical, too.

Update: Since posting this today, Yonah Freemark has posted a response of his own at the end of his original post.)

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Want more? Purchase Cable Car Confidential: The Essential Guide to Cable Cars, Urban Gondolas & Cable Propelled Transit and start learning about the world's fastest growing transportation technologies.


  1. About ridership estimates though. I think that CPT with such short wait time will probably induce much higher ridership that a comparable LRT/BRT line would where there is a greater wait time. That said, if you replace a busy LRT line, it may strain the capacity of a CPT that has a higher capacity. Not that I'm arguing against this technology, but I'm saying the novelty (at least at first) and short wait time may make it more popular than a bus line would be.
  2. I think that's incredibly prescient, Jeff. That potential does exist and the first Metrocable line in Medellin experienced that. Ways to avoid that: 1) Use a higher-end tech and plan for eventual increases in traffic. As long as the system has been designed to handle the additional load, more vehicles can be added relatively easily. 2) Recognize that the cost-effectiveness of cable means that you could install two lines (a couple kilometers apart from one another) for the price of one LRT line. In that way, not only do you get the capacity necessary, you also increase your network coverage dramatically. 3) Twin lines together such that more than one line utilize the same towers and/or stations. This has never been attempted before, but I've never heard anyone in the cable industry say it couldn't be done. Do that, and you double (or triple) capacity and create the potential for express lines that skip every other (or every third) station. Thanks so much for the insight!
  3. Thanks for the feedback. Adding vehicles brings up a question I have which I haven't found an answer to yet (since I'm new to this site, it probably has already been answered, I just haven't run across it yet.) Is it possible to dynamically change the number of vehicles circulating according to the time of day? For example: the early morning rush might require most of the vehicles (or is there a better term for this? pods?) to be in circulation, while during the off-peak, circulating that many vehicles may be unnecessary. It seems to me that removing extraneous vehicles during the off-peak period would decrease energy consumption and make the system more efficient in terms of resource use. The question is, it that possible and practical? Then again, perhaps that isn't even necessary.
  4. Jeff, It isn't really necessary because the systems are very energy efficient to begin with but, yes, you can do that and it's rather simple to do. I discuss that issue here.

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