[sustran] The only good monorail, is an old monorail (maybe).

[Eric Britton]

On Behalf Of Kerry Wood
Sent: Saturday, 30 January, 2010 23:50
  

Dear Eric

 

Monorails, hmm... maybe I should start with the advantages.

 

--          A very small land footprint without the cost of tunneling.

 

--          The capacity of rail or light rail.

 

--          A sexy look.

 

 

Surely with all these advantages there is a fortune to be made?

 

 

I suggest that the big disadvantages are 

 

--          Passengers are stuck up in the air when they want to be at
street level (especially in an emergency). In principle this is no different
from a metro.

 

--          Noise and visual. In principle these can be at least mitigated
(even by going underground in an extreme case), and at worst a monorail is
much better than a road flyover. Bridge designs and noise suppression have
improved since the Schwebebahn. Again, this is not so different from a
metro.

 

--          Getting trains from one track to another. 

 

You say that space is a problem if monorails need switches (I like the 'if')
but there are three related problems.

 

--          Switches are expensive as well as space-hungry. 

 

--          High-speed switches are impractically expensive. High-speed
monorails manage about 70 km/h through switches (very slow for a high-speed
train), by jacking a length of straight track into a curve. The displaced
end must move by the width of a train plus a bit of clearance, or say 3-4
metres, so the jacked section has to be very long.

 

--          Switches are minimised because of cost, and too few switches
lead to an inflexible system.

 

Operators struggle with any breakdown because there are few options for
getting a train out of the way. Delays are easier: there is nothing you can
do except make good use of any slack in the timetable.

 

In contrast, a late-running bus can end its run before an outer terminus,
transferring passengers to the bus that is now just behind. Then it can,
hopefully, start its shortened inward trip on time. Light rail can do the
same trick if the right loops or sidings are provided. Better still, either
system can be scheduled to terminate some services before the end of the
route. Heavy rail is not that flexible but can use switches to put a train
on to another track, another platform, a loop or a siding. 

 

A long monorail has excellent carrying capacity -- just like a railway train
-- but takes a long time to run through low-speed switches. For example, if
the speed limit through a switch was 10 km/h, a 200 metre train would take
80 seconds to go through a switch 20 metres long. More complex layouts would
take longer. When the train was clear, a departing train might face a
further wait while the switch was reset; a matter of two or three seconds
for rail but longer or much longer for monorail. 

 

I have pulled these numbers out of thin air, but they are enough to suggest
that there are problems with scaling up monorail beyond a 'demonstration
project'. Designing a terminus for a departure every two minutes might be a
technical challenge, especially for multiple routes. Success might be a
funding challenge and failure would be a commercial challenge.

 

Monorail systems never seem to have two or more routes running on one track,
as is common for rail systems. In principle passengers can interchange
between routes but in practice I don't think this is done -- does anybody
know of a city having two monorail routes? If it is not done, might the
reason be that the city authorities got wise before the second line was
built?

 

 

Kerry Wood

 

 

On 31/01/2010, at 6:07 AM, Eric Britton wrote:





 

Dear Ashok and others,

 

Thanks for sharing that Times of India article. Glad to see that someone is
pointing out one or two of the downsides of this inappropriate project.

 

But I am somewhat disappointed that no one on our Sustran list thus far
seems to want to step forward and help us enumerate all the reasons why
monorails are such a brain dead concept.

 

Someone tell me that I am wrong, but among the many flagrant
disadvantages/absurdities of the monorail concept for cities, include:

 

1.    They cost far too much money given the level of service they provide




2.    They don't (really) go anywhere (i.e., where they are needed in a
many-to-many world)




3.    Good transportation is supposed to be as close to seamless as we can
make it - and they are anything but, cut off from the rest as they are by
definition




4.    Limited capacity (per buck spent)




5.    They are a visual intrusion (scar) on the city scape




6.    The ignore, they actually degrade the street in many ways - which is
the very heart of the city




7.    They are, to a pylon, to a track, to a car, to a station, ugly as sin
(my old grandmother's expression).




8.    If they need switches, the space requirement becomes complicated.




9.    Emergencies are very messy.




10. They don't do the basic job that is needed.




11. They saddle the city with debt.




12. To be "cost effective" (ho ho), they cannot provide affordable service
for the majority




13. They are not sustainable by any measure




14. They are often the project of industrial-financial-political interest
alliances and even, if one digs deep, corruption. (As so often is the case
with big ticket transport and other public investments.)

 

By the way, did anyone note that almost to the day as Mumbai joyously
welcomed their first test car the Las Vegas Monorail Co has filed for
bankruptcy?  Just thought I would mention it.

 

In summary: They are so awful, so thoroughly dysfunctional that I even have
difficulty in anyone trying to justify them (or not) in terms of anything
like "relative CO2 efficiency". This I see as a splendid project for a MA of
PhD student sharpening their tools, but when it comes to the politics of
transportation they defy common sense.

 

So out they go.

 

(I invite comment and corrections as always).

 

Eric Britton

 

PS. Ask me what's better, what gives more sustainable transport bang per
buck than a monorail?