ULTra PRT (urban light transport – personal rapid transport) vehicles have started operating at London’s Heathrow Airport. BAA, the operationg company for Heathrow Airport, needed to provide a means of travel from the new terminal 5 to remote parking. Comparing several options, ULTra PRT provided a solution that was
ULTra PRT Advantages
The PRT concept has been around for a few decades. Heathrow is the first full-scale implementation of the concept. By installing a PRT, lower value land use like parking lots can be located further from the terminal. This less costly solution to public transit also has the advantages of personal transit. The personal air-conditioned vehicles do not have to stop for other passengers. They run at about 25 mph on a dedicated track with off-road stops, avoiding all forms of traffic control and congestion. (No stopping behind non-moving vehicles.) The “podcars” are in constant communication with a control center but operate autonomously using laser sensors. There is also a failsafe to keep vehicles from hitting one another.
The technology for some individual components is not cutting edge, but the system shows what can be done even with available equipment. The vehicles use a 4 x 45Ah, 48-volt lead acid battery pack that is recharged between stops and recycled when they are no longer usable. The front wheel drive motor typically draws about 2KW. The cars are relatively light and run on 13″ wheeled, tubeless tires. The body is of ABS plastic and steel with acrylic glazing.
Guideways provide a track for the vehicles and a curb for the guidance system. They are not powered and don’t contribute to the operation or communication of the vehicle with the control which is done wirelessly. Stations are less costly as well because the vehicles wait for people rather than large masses of people waiting for a ride. Like taxis gathering after a theater performance, we can expect control will schedule more units to wait for incoming planes.
Potential PRT systems are being studied as replacements for transit systems throughout the world. At Heathrow, there is a study to continue the system into the central terminal to relieve congestion. Buses and trains can operate very efficiently when full during rush hours. During off-peak hours it would be more economical to operate smaller vehicles, but capital costs would rise with multiple vehicle types, some of which would always be idle. By operating closer together than vehicle traffic, a PRT system can make up for the size of the cars. It may also eventually be possible to operate the units on wireless transmitted power for an unlimited range and no charging times. For now, though, you have to go to Heathrow terminal 5 to catch a ride on the world’s first operating PRT system.
All photos from ULTra PRT
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