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Cap'n Transit

I understand that monorails had lots of glamour in the fifties and sixties, but I thought the Simpsons killed that. I have the impression that there are more people starry-eyed over "PRT" than monorails.

Branching is a big deal. Investing in a technology that doesn't branch means basically limiting service to single lines or loops. But I have to point out that the Paris Metro only has two branches in the entire system. (The RER has lots of branches.)

Also, the #7 el goes right through my neighborhood, and if it were smaller, lighter and especially less noisy it wouldn't be so bad. Still, I like my express service. But why can't they run monorails in tunnels?

Jarrett at HumanTransit.org

I don't think there's any reason you CAN'T put a monorail in a tunnel.
Doing so eliminates everything that makes the technology appealing, but I
suppose you could do it on a particular critical segment of an otherwise
elevated line.
Branching dissapates frequency, which is why it's done very little on the
Paris Metro (and too much, IMHO, on the London Underground). Branching
makes more sense on the RER because the dissapation of frequency matches the
shape of that market: you want high frequency through the city but don't
need as much on the outer-suburban branches.


I think that a well designed elevated heavy or light rail line can achieve aesthetics comparable to a monorail. For example these BART tracks http://upload.wikimedia.org/wikipedia/commons/f/fd/Raised_BART_Tracks.jpg in Walnut Creek, CA are fairly attractive as such things go. Of course as other people have pointed out its also easier to run conventional rail at grade level, in tunnels or in trenches which means that in places where the train isn't stopping it's easier to minimize it's impact (do you really want an elevated train running over your back yard every 10 minutes, for example).

Actually the comparison of BART's broad gauge heavy rail to a monorail is particularly convenient since BART happens to be building both a heavy rail extension and a monorail. BART's 5.4 mile Warm Springs extension is expected to cost $164m/mile and is coming in under budget while BART's 3.2 mile monorail is costing $171m/mile. Further this isn't comparing an at grade heavy rail extension with an all-elevated monorail. Demonstrating the advantages of conventional rail technology, about 1/5 of the BART extension will run in a tunnel to avoid the visual impacts of running an elevated rail line through a park while the rest will be at grade.

Cap'n Transit

Thanks, Jarrett! That makes sense.

So you only want branching when the lines spread out so much (due to a radial configuration) that they no longer are within a reasonable distance of the population - but the population density is low enough that the split service doesn't become overcrowded.

The other possibility is in a system like in New York or London, where individual routes can switch from one line to another to reduce the necessity of transfers.

If you don't have either of those conditions, then it sounds like the only disadvantage to a monorail is the shadow. And a lot of that depends on how much of the street it fills up.

Here along the #7, there's a big difference between the parts on Queens Boulevard where there is enough width so that the sidewalks aren't in shadow versus the parts along Roosevelt Avenue in Jackson Heights and Corona where it feels like there's a lid on the street. In the middle are the parts in Woodside and Corona Plaza, where Roosevelt runs diagonal to the street grid, allowing for triangular parks along the line; it's also much more elevated there. The main problem there is noise.

Jarrett at HumanTransit.org

Winston. True enough, and BART is far from being a cheap rapid transit technology.


I tackled this same subject on MetroRiderLA two years ago, though I am decidedly more stubborn on monorails:

You can't spell monorail without M-O-R-O-N

Despite the clever title, it isn't so much an indictment of the mental capacity of monorail supporters. What it is, though, is an attempt to discover why the monorail as a techonology never caught on despite its benefits.

"Monorail ... has a fundamental flaw: one track offers NO economic or operational advantages over two tracks. Monorail ... tries (and fails) to reinvent a wheel that does not need improvement."


It's not a track, it's an "elevated duorail"! Seriously!


The best kind of monorail: gyro-monorail.


Monorails have a number of problems, some of them intrinsic to the technology. For one thing, it's a rubber-on-concrete interface, with all the attendant ride quality (it's bumpy!). Another problem is that the support structure is also the running surface. This means that you have to adjust the whole structure to make a properly level surface, whereas with a railroad you can just adjust the rails. The switches are complicated, expensive, and slow. A pneumatic railroad switch takes under 3 seconds to unlock, move, and re-lock. Plus, because monorail switches are so huge and cumbersome that putting one in is a huge major project, while some street railways actually have portable crossovers that can be installed in a few hours, and even a regular crossover can easily be installed in a weekend.

Another problem, not necessarily inherent to monorails, is that there isn't really any standard for them, and it's pretty much impossible to adapt a train made for one kind of beamway to a different kind. Conventional trains also have incompatible track gauges and wheel profiles, but this can be worked around with some effort by swapping trucks, and indeed has been done on occasion, with streetcars and even rapid transit vehicles, not to mention the regular truck-swapping and gauge-changing operations on mainline railroads.

Alon Levy

The New York splits can be a real pain when it comes to service delays. A delay or a nasty GO on the 5 in Brooklyn can cascade to the 3 in Harlem. Systems that have a choice about this matter, like Toronto, prefer to run each line independently from the other lines. Even the RER has five separate lines without track-sharing except for one section between line B and line D.


The Monorail Society (www.monorails,org) has this in its entry for the monorails being build in the Malaysian city of Putrajaya:
"Putrajaya Monorail will eventually consist of two lines. One line will be 12 km long with 17 stations and the second will be 6 km long with six stations. The system will be mostly underground on the central island and elevated in the city's 'mainland' areas. The completion of the Putrajaya Monorail has been delayed until there is a higher occupancy of the new city."
(emphasis mine)

Monorail requires a large gap beside the track, making it unsuited to most street-level applications, but it would be more accurate to say "must be grade-separated) than "must be elevated".

Just FYI


Jarrett, you cite monorail's "inability to branch", but don't give any reason for it.
The monorail at Walt Disney World has 2 branch points: the loop of track that serves Epcot is separate from the two loops that serve the Magic Kingdom and resorts at Walt Disney World, and trains move from one to the other via a switch, and also there is a switch to move train on the Magic Kingdom line onto a spur to the maintenance barn for storage at night.

anonymouse, while I grant that the fastest monorail switches I know of are at least 4 times as slow as the fast rail switch you mentioned, I think in most applications a switch able to cycle completely in under 12 seconds, as the ones at Walt Disney World do, is more than adequate.
You can learn more at http://www.monorails.org/tmspages/switch.html

Also, on the subject of "standards": while it is true that "it's pretty much impossible to adapt a train made for one kind of beamway to a different kind", there are only a few basic types (two broad categories - straddle or suspended - each divided into 3 basic subtypes), within those types slight variation in the width of the guidebeam is fairly easy to adjust for at manufacture.
Most monorails large enough for transit use (not "peoplemovers" are not just the straddle type, but use the ALWEG style of bogie and beam, and the widest bean used by a current manufacturer is only 7.5 inches wider than the narrowest.

In order to fairly judge which technologies are best suited to addressing a given problem, one needs first of all to have an accurate picture of the advantages and disadvantages each technology has. Remember to be suspicious of anything bad about monorail said by someone trying to sell you light rail, and also of anything bad about rail said by someone trying to sell you monorail: both have a reason to lie, as they advocate one technology over the other.

For the record, I think monorails are cool, so my bias would be pro-monorail, but I try to keep that in check.

Jarrett at HumanTransit.org

Thanks, SpyOne. I think monorails are cool too.

Re branching, thanks for the link. I don't claim to be an expert on the technology, but in my encounter with it as a planner, around the Seattle Monorail Project planning, it was clear that branching was going to be problematic for the technology they and their contractor hand in mind. I'd welcome links from anyone who was closer to that project and better understands the issue.

The Monorail Society's images that you point to, even though prepared by advocates, do make clear that a monorail switch involves moving a very large object -- a segment of the beam. This has to be slower, less energy efficient and more cumbersome than conventional rail switches.

J.D. Hammond

I'm not sure why it's not showing up, but I did respond to a number of these criticisms on my own blog, and mentioned that the Osaka monorail is branched. Most other monorail systems have non-revenue or terminal switches that are maybe a little more complicated than a conventional rail switch, but not particularly more cluttered in the context of elevated rail.

I'd really like to know where Matt Groening got the impression that monorail is not transit, or is a distraction from "actual" transit, much less this idea that high-capacity transit kills communities. Because that, in a nutshell, is the basic idea behind "Marge Vs. The Monorail". Some people think it says hilarious things about monorails; I think it's poisonously anti-transit in a way that's highly unconstructive and surprising for a writer who's otherwise shown himself to be rather progressive. If he wrote a similar episode about streetcars or light rail or BRT, I think there would be understandable outrage. I don't see how monorail is exceptional.

And, well, you can run a monorail in a tunnel; it's been done in Japan a couple of times. But I'm not sure why you'd want to, other than in a few special circumstances to facilitate a transfer to an underground rail network or something. Or perhaps an underground line could be rehabilitated to monorail, but again, why? You've already got a grade-separate underground line in that situation.

J.D. Hammond

I'm not sure who wrote this, but no one calls conventional rail "duorail" other than monorail partisans. That said, it's mostly true; Oakland AirBART is an automated VAL system. An apples-to-apples comparison here would probably be with JFK's AirTrain or the Canada Line in Vancouver.

J.D. Hammond

Actually, most rubber-tired monorail systems do have at least one operational advantage over conventional rail: improved traction. But you could probably say this about a rubber-tired VAL system as well.


My parents had both taken Theater as their minor in college, so I was very familiar with The Music Man as a child. Thus, I quickly spotted the Marge vs The Monorail episode as a parody of The Music Man, thus I didn't think of it as particularly anti-monorail.

In The Music Man, the con-man central character is trying to sell the town instruments and uniforms for a children's band. This is not a product without value, although the town's need for it is entirely fictional, as he has manufactured a perception of crisis and offers the band as a solution to that crisis. However, it is a product that the salesman has no intention to deliver: he plans to collect the money and then skip town.

Monorails are not inherently worthless in that episode. In fact, the man who designed the monorail seems to have designed a useful solid product. However, Lyle Lanley (the salesman) has changed the design to make something that looks good and costs as little as possible.

A major difference would be that in the Simpsons, the crisis is real (crumbling streets due to poor maintenance).

I have found at least one website that expresses opinion that the monorail in that episode was a thinly veiled metaphor for the Los Angeles Subways, but I think that may be a case of seeing what you are looking for.


J.D., your example sounds more like the merits of rubber over steel tires, not specifically the merits of one rail over two.

Monorail has some very significant hurdles that it has not been able to overcome: a very limited knowledge tree among vehicle and guideway engineers, proprietary and custom guideway and vehicle engineering, little to no interoperability possibilities, and switching costs from conventional rail outweigh the potential cost or operational gains.


I think the main reason why monorails haven't taken off in the western world is because they are being pushed towards the wrong application. Monorails should not be an alternative to light rail, but should be considered as an alternative to heavy rail. When a city chooses to go the heavy rail route, it generally means that they have no intentions of running at grade since most heavy rail is powered by a third rail. However, if a city chooses heavy rail, they must decide on whether to go underground (VERY expensive) or above ground (visual eyesore). With above ground monorail, it is not, or at least less of an eyesore.

Also, while I have never been on a monorail outside of Disney, I think they can fit into an urban setting quite nicely. The Naha monorail is more aesthetic than older builds, and the Wuppertal, Germany monorail is over 100 years old and blends in with the turn of the century architecture quite nicely. I also like the look of the Sydney monorail, though ironically I don't know if it would look as pleasing if it was built to a higher standard (high capacity trains and larger beams, two way line).


Although infrastructure of the venerable Wuppertal monorail (and truly monorail at that, running on a single steel rail) has engineeering interest, I could never describe it as 'blending in'. Also as a single route — with amazingly sharp turnaround loops at each end on which the car geometry has to be seen to be believed — it is an ancient and prime example of the branching problem, whether for routing or for the equally important depot purposes.
As for the Sydney monorail, that is little more than a one-way touristy fairground ride; viable transit for Sydneysiders it most definitely is not.


There was no mention of http://www.urbanaut.com/ which was designed by a former Alweg engineer. It's being installed in South Korea.


[...] See also Human Transit take on it and on technology driven approach in general like the monorail [...] (it is manual trackball to http://voony.wordpress.com/2010/02/04/hyvonis-or-the-hydrogen-bus/ since the automatic doesn't seems to work)


Any impressions Matt Groening may or may not have gotten about transit are irrelevant, as "Marge vs. the Monorail" was written by Conan O'Brien.

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