This mode incorporates
a single rail as its principal track for passenger vehicles (or
freight). The guideway (single rail) is normally elevated but can
also be built at grade, below grade, or in subway tunnels. Vehicles
are either suspended from or straddle a narrow guideway. The monorails
distinguishing feature, however, is that the vehicle is wider than
the supportive guideway.
The monorail has caught the fancy of the public since its first
appearance in 1825. At this writing, there are about forty-nine
monorails operating in the world. While a portion of these involve
transportation at zoos, amusement and theme parks, and excursion
rides, there is good representation of monorail systems in the transit
industry.
For these purposes, we define "transit" to mean transportation
of the public on a system comprising two or more stations. In the
modern era of transit monorails, Japan operates seven full-scale
monorail systems and has several new lines in the planning stage.
The Toyko/Haneda monorail, built in 1964, was the first to use switches
for directional control. Seattle's 1.3-mile monorail system was
opened in 1962 for the World's Fair in that city and is still operating
today. Efforts are underway to extend the original system into a
city wide transit service. Perhaps the world's most popular monorail
system is at Disney World in Orlando, Florida, operating over 14
miles with passenger loads of one hundred thousand per day.
Over the 175 year development period of monorails, guideway design
has evolved from complicated steel lattice type structures to single
concrete long span beam structures supported by concrete columns.
The design goals to slenderize the profile, present a nonintrusive
vista, minimize cost, and simplify construction have been accomplished
through the use of concrete.