The Future: A New Urban Transit System Stands a Chance of Getting
People Out of Their Cars
by Joan Blatterman
Reprinted from Architectural Record (July, 1997, p. 174). Copyright 1997
by the McGraw-Hill companies. All rights reserved. Reproduced by permission of the
I have seen the Future (on video) and it just
might work. This month's column describes a developing light-rail technology that promises
to reduce traffic congestion with fixed guideway transit that fits easily into an existing
urban street grid; costs much less than other light- or heavy-rail systems, subways, or
roads in crowded cities; and, unlike buses, should be really fun to ride.
On a recently decommissioned navy yard in South Carolina sits a quarter-scale model of
a transit idea that needs only a funding boost (from ISTEA's Congestion Mitigation and Air
Quality program?) to go into real-life operation. In development over the last 10 years,
the concept has received lots of favorable buzz in engineering and mass-transit circles
here and abroad. Called System 21 , the transit system has
streamlined, podlike cars and sleek, slender pedestals. And the engineering is elegant.
Unlike other monorail-type equipment, which needs expensive dual tracks or offers only
closed-loop layouts, this design provides for simultaneous two-way traffic on a single,
6-ft-wide hollow-wedge elevated beam. Individual cars, constructed of a rugged
fiberglass/plastic composite, are cantilevered from either side of this beam by a steel
outrigger structure; steel wheels on each car travel in a contoured rail truck recessed in
the beam. Standard commercial DC power is delivered via the beam to alternators onboard
each car, which in turn supply AC current to each of the independent drive wheels. Single
cars can hold about 50 passengers, with extra space available for special-needs users.
Cars and support beams are modular, and easily connected. (Futrex claims the entire system
can be removed and reassembled elsewhere.) Train makeup can be adjusted quickly to meet
peak-hour traffic requirements without need for a switching yard.
Working from an original design by aerospace engineer Lawrence K. Edwards, the
fixed-guideway transit scheme is being developed by Charleston, S.C.-based Futrex, with a
group that includes the Battelle Memorial Institute, transportation consultants Frederic
R. Harris, Inc., and engineers Powers Design International contributing significant
technical and financial assistance. The government also anted up a $1.25 million
seed-money loan from a Commerce Department fund intended to advance American technology.
(Canada, France, and Germany all have substantial urban-rail manufacturing capacity, but
this equipment is considered by transit experts to have limitations, such as a price tag
in the $50 to $70 million-per-mile range.)
The consortium is planning to build a 1.6-mile full-scale version at Charleston
International Airport that will demonstrate System 21's ability to carry large numbers of
passengers safely at speeds of up to 60 miles per hour. (Speeds of up to 100 miles per
hour will be possible eventually.) So far, model-test results appear to validate the
proprietary structural and mechanical design elements.
While System 21 incorporates existing steel-wheel drive technology, it has many
unique, patented features, including the method of attaching the cars to the beam and the
mechanics of grade-separated branching, which let the cars switch direction smoothly.
System 21 should be able to fit relatively unobtrusively into existing streets, where
design issues are air space, span lengths, and minimizing intrusion at grade level. System
21 can take on and discharge passengers, round tight curves (the system has a 90 degree
turning radius), and switch from branch to main line-all 16 feet in the air. A station
able to accommodate four cars would need a 14-by-120-ft ground-level landing area to
provide station access by stairs and elevator. In its current, steel-framed configuration,
System 21 can span 84 feet from column to column; planned precast-concrete structures will
be able to carry about 100 to 120 feet between supports. The guideway columns are slender,
requiring only a compact, 18-in.-high concrete base pedestal. Site-work involves just the
preparation of the 7-by-7-by-2-ft foundation for each column, supported by four pilings
driven to bedrock. All other components-beams, stations, branching points-are manufactured
and assembled off site, to be placed by trucks and lift cranes as foundations are ready.
While the standard height is anticipated to be in the 16-ft range, easily clearing
ground-level truck traffic, the system can be placed just a foot off the ground-say in a
fenced right-of-way. Heights of 40 to 50 feet are possible, and trains can handle grades
of up to 10 percent. Futrex says the beam-mounted rail system can meet hurricane-force
winds and Los Angeles-caliber seismic loads.
And about that video: call 843-760-4500.
Last modified: August 19, 2007