Why is the monorail system not as widespread?

[daveklepper]

There is almost off-the-shelf technology that can make an elevated railroad quieter than a surface line.  It involves "Barriers than can become walkways for maintenance."   This is discussed in my paper "Further thoughts on railway noise," in the March-April issue of Noise Control Engineering.   As applied to the approximately 20% of the route mileage of New York City's rapid transit sstem, and excepts follow:

In the first paragraph of the first reference, it is stated that 

noise  barriers  present  a  hazard  to  track  workers,  adversely 

affect mechanized track maintenance, and present a permanent 

visual intrusion....

....possibly the idea shown in Fig. 1 can present an answer to the first two problems in many cases, and keeping the noise sources in the vehicle as low as possible can provide the answer to the third. Figure 1 was prepared for mitigation of one of New York Cityʼs worst noise problems, and applies directly to many “subways on elevated structures” in that city, primarily The Bronx.

 

The need for three tracks on these structures is less great 

than when the structures were built, and the weight savings 

possible by eliminating the center track, by using single track 

bi-directional operation during heavy maintenance periods, and 

by using skip-stop express operation during rush hours instead 

of separate one-way local and express services, which in any 

case are provided on a small fraction of the elevated subway 

lines.

I am confident that such firms as Wenger, Overly, Industrial Acoustics, and Trux can engineer walkable surfaces with efficient sound absorption and durable longitudinal hinges to make the concept practical for many situations. Ten dB Noise Reduction should be realized in many cases. 

Note that the rigid track structures, ties or sleepers imbedded 

in concrete or rails themselves imbedded in concrete (“slab 

track”) is not recommended where noise control is critical. 

Even  where  resilient  surrounds  of  rails  and  ties  and  clips 

are used, the slabs tend to radiate forward and to the rear of 

the passing train. This need not be a problem in subways or 

underground  Metros,  but  can  compromise  noise above  ground.

Back issues of the magazine should be avialable in any engineering library, and I will be glad to send a pdf of the aritcle to anyone askiing at [e-mail].

There is also the concept of the elevated light railway, based on the original Dr.Charles Harvey West Side Patend Elevated Railway from Greenwich and Broom Streets to 9th AVenue and 29th (30th?) St. before crossties were introduced when dummy steam locomotives replaced cable propulsion.  The "skyprint" was and would be in the future, no greater than a monorail, possibly less.   But, wihtout side walkways of any type, and without anything to walk on between rails directly supported resiliently on the two longitudinal beams, a fleet of cherry pickers would need to be on-hand for emergency evacuation.

[CSSHEGEWISCH]

Much of the Midway L (Orange Line) is built on concrete superstructure not unlike an elevated highway.  The roadbed on these sections is conventional track and ballast and excessive noise is not a major issue.

[BroadwayLion]

Monorails really do not add anything to transit, and the equipment is very expensive and specialized. The system in Seattle has all of the problems of a conventional el and then plenty more.

Modern concrete construction can build elevated strcutures that are just as slender and quiet as anything a mono-rail can do. There is no reason to shy away from modern elevated city transit except of course people's fears that you would be brining back your great-grandfather's el.

LION thinks that the experementation with rubber tiers was a mega-flop which is different from a peta-flop.

Oh well, accoring to LION, with few exceptins, monos are limited to amusement parks.

ROAR

[Paul Milenkovic]

"The mob has spoken" -- is that a reference to the TV's Simpsons and the Monorail Mania in the ficticious Springfield?

I often find short responses as to why a technology has failed or has not caught on to be deeply unsatisfying.  There is no explanation offered as to what people were trying to do in the first place and how the tech failed to meet those goals.

With a transit system, you can either go below the street (subway -- very expensive), at street level (light rail -- either requires a special right-of-way that still has grade crossings or operates as a streetcar and is stuck in traffic with everybody else) or above street level.

The most well-known above-street level trains are the El, still used in Chicago, once used in New York but replaced by subway lines.  My recollection of the Chicago El (elevated lines) is that they are massive structures that many people feel blight the street and the neighborhood.  The steel-on-steel-on-steel wheel-on-rail-on-elevated structure is also very noisy.

The idea behind monorail-as-elevated-transit is that a more slender, visually appealing, quieter, and (this is a stretch) lower cost concrete beam substitutes for the clunky El.  At least that was the idea behind the Alweg system -- Seattle, Disneyland, (Las Vegas "Strip") monorails.  As mentioned above, one of the problems is a really hard time switching between diverging routes.

 

But the rubber-tire supported Paris Metro, OK, a subway and not an elevated line, has been duplicated in Montreal and other places?  Then there are various airport "people mover" trams using everything from magnetic attraction maglev (which may account for the remark about the complicated control system) to variations on rubber-tire supported trains?  Many of them being elevated lines using concrete beams, but a different guidance system than the Alweg?  Are these "monorails" or do we call them something else?

So maybe monorail is not a technological or financial failure but instead part of a suite of systems that may be a good fit to particular applications where the demand is for an elevated transit system, an easier-on-the-eyes concrete beam guidway, and a lower-noise rubber tire support system?

[D.Carleton]

"Sorry, Mom, the mob has spoken."

[LNER4472]

It's more of a Shelbyville idea.........

[BaltACD]

Cost/benefit ratio is in the dumpster.

[Firelock76]

All of the above.  In a nutshell, monorails are great in theory, but in fact aren't the panacea everyone thinks they are.

[NorthWest]

Monorails take up essentially the same amount of space as a conventional railroad, and cannot have grade crossings.

[54light15]

Plus, you're married to the technology of whoever builds the system. Not everyone can build a monorail, yet many manufacturers can make equipment that runs on two rails. 

[blue streak 1]

Without active controls  ( almost half the cost of a F-16 ) speeds are limited to about 35 MPH MAS

[CSSHEGEWISCH]

This notion has been discussed repeatedly in the past.  Monorails lack flexibility and are not really suitable for anything beyond short loop routes.

[zkr123]

With people looking for other forms of mass transit, monorails could be the solution without clearing chunks of land. I'm not talking about airport trains but through towns/cities.