The Beamways PRT system

A lot of tradeoffs have had to be made in the design of the Beamways PRT system. Below the outcome of these tradeoffs is presented, along with their practical consequences.

Guideway properties

The Beamways guideway is designed for minimal visual intrusion in the cityscape and to give a high capacity at a reasonable investment level.

Suspended system leads to a higher beam position

As the cabin is located under the beam and the cabin floor must be about 5 meters above street level the beam itself will be about 7 meters above ground. This gives a couple of advantages.

The most important advantage is probably that the beam looks thinner from the ground as it is further away from the eye of the beholder. An equaly sized beam blocks 60% more of the sky in a supported system than in a suspended system.

Another advantage with a higher beam position is that it is possible to transport high goods if the PRT traffic is temporarily suspended. There are high units being transported on our road network, for instance prefabricated house sections. With a supported system you get 2 m less margin for high road transport than with a suspended system.

Downward facing beam slot for excellent weather proofing

As the Beamways vehicles are suspended below the beam the rod connecting the wheels inside the beam with the cabin below exits through a slot in the bottom side of the beam. This reduces the risk of snow or debris entering the beam compared to systems with an upwards facing slot and systems where the wheel run on the top surface of the beam.

Lean beam for minimal visual intrusion

By running the beams in pairs for double direction traffic, Beamways can make do with leaner beams than single-direction systems. The cross members between the beams take up the torsion forces created by centrufugal and wind loads. A single direction system has to cope with these forces using only one beam, which makes a wider and/or deeper beam necessary.

This document makes apparent that there can be a real difference in visual intrusion between systems.

25 m (80 ft) post distance to pass over intersections

To be able to cross most intersections in cities a distance between posts of at least 25 m is required. This is the main reason that the Beamwasys system is designed for this post distance.

Double direction beam offers high capacity and speed

Double direction netwroks offer about three times the capacity of single direction networks. The reason for this being more than twice is that in a single direction network each trip is up to 50% longer (if the mean trip length is 5 km). This in turn is caused by the guideway only going in one direction at each stop causing extra “backwards” driving compared to the desired direction.

At Beamways we are convinced that  PRT will be very popular and heavily used. It is important to invest in a system which has a capacity sufficient when the network is built up in the entire city. For this reason the Beamways system is optimized for double direction lines even if it is of course possible to build Beamways systems with single direction parts. Those parts would however have to have a closer post spacing or a somewhat larger beam.

Tight turns gives large flexibility

In many cities there are areas where space is scarce but where it would still be preferred to have a PRT line. To be able to meet these demands we have designed the Beamways system so that extremely tight curves can be negotiated. This also makes crossings between double direction lines possible to design in tighter areas.

Steep slope ability enables ground level stations

Beamways system guarantees a high enough friction to handle very steep slopes. As the cabin can be tilted to keep the floor level in all slopes the ride comfort is not impaired. This enables stations to be placed at ground level in many places.