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monorail: Definition and Much More from Answers.com

  • ️Mon Jan 15 2007

The KL Monorail in Kuala Lumpur, a colorful straddle-beam monorail

A monorail is a single rail serving as a track for a wheeled or (magnetically) levitating vehicle; also, a vehicle traveling on such a track.

History

Gyroscopically balanced monorail (1907) by Brennan and Scherl

Attempts at creating unconventional railways have been made since the latter part of the 19th century. Usually these have been claimed to be more efficient, faster or cheaper to construct than conventional railways.

Several attempts have been made to create a system in which a double-flanged steel wheel operates on a single rail similar to the railroad type of rail. The suspended Wuppertal monorail (1901) described below is the only surviving monorail of this type. Gyro monorails, which are gyroscopically balanced on a single rail, have been tested but never developed beyond the prototype stage.

Monorails have both benefited and suffered from their novelty and concept of modernity. When The Walt Disney Company placed a monorail in their Disneyland theme park in 1959, it exposed large numbers of visitors to the transportation form in a credible though miniature transit setting. At the same time, however, the Disneyland monorail and others built at other Disney properties and amusement locations have tended to identify monorails with amusements rather than practical transportation. [citation needed]

The popular press in the U.S. in the mid 20th century often featured monorail ideas in a "transportation of the future" context, along with images of personal "rocket backpacks" and popular space travel, creating interest but also confusion as to which ideas were fads and which might become reality.

According to Rod Diridon, director of the Mineta Transportation Institute, the real reason monorails in the United States came to be typecast with theme parks and never took flight was because "it got caught in what all mass transportation got caught in the '50s and '60s -- the love affair with the automobile." [1]

Types and technical aspects

The Schwebebahn Wuppertal, the world's first suspended monorail

Modern monorails depend on a large solid beam as the vehicles' running surface. There are a number of competing designs divided into two broad classes, straddle-beam and suspended monorails.

The most common type of monorail in use today is the straddle-beam monorail, in which the train straddles a reinforced concrete beam in the range of two to three feet (~0.6-0.9 m) wide. A rubber-tired carriage contacts the beam on the top and both sides for traction and to stabilize the vehicle. The straddle-beam style was popularized by the German company ALWEG.

There is also a form of suspended monorail developed by the French company SAFEGE in which the train cars are suspended beneath the wheel carriage. In this design the carriage wheels ride inside the single beam. The Chiba Urban Monorail is presently the world's largest suspended monorail network.

Power

Almost all modern monorails are powered by electric motors fed by dual third rails, contact wires or electrified channels attached to or enclosed in their guidance beams. There is a startup called Metrail that has built a hybrid prototype using diesel power to generate electricity for the motors.

Magnetic levitation

Transrapid maglev on monorail track

Magnetic levitation train (maglev) systems by the German Transrapid were built as straddle-type monorails, as they are highly stable and allow rapid deceleration from great speed. When in full-speed operation maglev trains hover over the track and are thus not in physical contact with it. It is the fastest monorail, running at up to 311 mph (501 km/h).

In addition, Linimo was inaugurated in Japan in 2003.

UniModal has patented the SkyTran "pod monorail" which would use an Inductrack passive maglev monorail track for personal rapid transit. The system remains in the conceptual stage.

Switching

Some early monorail systems--notably the suspended monorail of Wuppertal (Germany), dating from 1901 and still in operation--have a design that makes it difficult to switch from one line to another. Some other monorail systems avoid switching as much as possible, by operating in a continuous loop or between two fixed stations, as in Seattle, Washington.

Sydney's monorail avoids switching by operating in a single loop.

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Sydney's monorail avoids switching by operating in a single loop.

Current operating monorails are capable of more efficient switching than in the past. In the case of suspended monorails, switching may be accomplished by moving flanges inside the beamway to shift trains to one line or another.

Straddle-beam monorails require that the beam structure itself be moved to accomplish switching, which originally was an almost prohibitively ponderous procedure. Now, however, the most common way of achieving this is to place a moving apparatus on top of a sturdy platform capable of bearing the weight of vehicles, beams and its own mechanism. Multiple-segmented beams move into place on rollers to smoothly align one beam with another to send the train in its desired direction, with the design originally developed by ALWEG capable of completing a switch in 12 seconds.[1] Some of these beam turnouts are quite elaborate, capable of switching between several beams or even simulating a railroad double-crossover.

In cases where it must be possible to move a monorail train from one beam to any of a number of other beams, as in storage or repair shops, a traveling beam not unlike a railroad transfer table may be employed. A single beam, at least long enough to carry a single monorail vehicle, is aligned at an entry beam to be mounted by the monorail cars. The entire beam then rolls with the vehicle to align with the desired storage beam.

Systems similar in appearance

The term 'monorail' is often applied by members of the public to any modern elevated railway, particularly automated ones such as the Docklands Light Railway, Vancouver SkyTrain and the JFK AirTrain, but this usage is erroneous; these systems use the same twin rails and electric third rail as most underground metros and some main-line railways.

Advantages and disadvantages

Old Soviet monorail in Ukraine (now abandoned)

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Old Soviet monorail in Ukraine (now abandoned)

Advantages

  • The primary advantage of monorails over conventional rail systems is that they require minimal space, both horizontally and vertically. Monorail vehicles are wider than the beam, and monorail systems are commonly elevated, requiring only a minimal footprint for support pillars.
  • Due to a smaller footprint they are seen as more attractive than conventional elevated rail lines and block only a minimal amount of sky.
  • They are quieter, as modern monorails use rubber wheels on a concrete track (though some non-monorail subway systems, like certain lines of the Paris Métro and all of the Montreal metro, use the same technique and are equally quiet)
  • Monorails are capable of climbing and descending steeper grades than heavy or light rail systems.[citation needed]
  • Unlike conventional rail systems, straddle monorails wrap around their track and are thus not physically capable of derailing, unless the track itself suffers a catastrophic failure, which is why monorails have an excellent safety record.

Disadvantages

  • Monorail vehicles are not compatible with any other type of rail infrastructure, which makes (for example) through services onto mainline tracks impossible.
  • Monorail lines cannot be built at grade.
  • In an emergency, passengers may not be able to immediately exit because the monorail vehicle is high above ground and not all systems have emergency walkways. The passengers must sometimes wait until a rescue train, fire engine or a cherry picker comes to the rescue. Newer monorail systems resolve this by building emergency walkways alongside the entire track, at the expense of visual intrusion. Suspended railways resolve this by building aircraft style evacuation slides into the vehicles. Japanese systems use the next train to tow broken down trains to the next station, but this has yet to occur.
  • Turnouts, especially high speed ones tend to be difficult. Traversers might be substituted.

+ Monorail infrastructure and vehicles are coming from one manufacturer - there is no multisouring and competition of different technologies and manufacturers in one network as in UIC railways systems.

Monorail systems

Main article: List of monorail systems

References

  1. ^ The Switch Myth. Retrieved on 2007-01-15.

See also

Wikimedia Commons has media related to:

External links

Monorails in general

Specific monorails

Monorail advocacy groups

  • Austin Monorail Project - a non-profit advocating monorail transit for Austin, TX
  • 2045 Seattle - a grassroots movement that supports the construction of rapid transit monorail in Seattle, WA
  • The Monorail Society - an all-volunteer organization founded to foster more awareness and promote this unique method of transportation

Organizations/views opposing monorails

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