28.06.13
Flyda Mass Transit Systems
Flyda’s trains are designed to operate elevated, at grade and in tunnel, seamlessly transiting from one mode to another. The Flyda technology was patented but is now in the public domain and Flyda Ltd is no longer in business. However Flyda's technology continues to be valid and potentially hugely valuable for new urban transit systems.
In new urban transit systems, infrastructure construction is by far the greatest source of costs and produces by far the greatest environmental impact. Flyda's technology can save a major part of the infrastructure costs and thus reduce the overall costs dramatically. It can also reduce the environmental impact and local resistance equally dramatically.
Flyda overhead guideways (see attachments) should not be confused with monorails. Similar in scale and cost to a single direction monorail, Flyda elevated guideways carry two guideways (e.g. Northbound and Southbound), not one! Unlike monorails which may swing and can be unstable in trains, Flyda vehicles, with widely separated wheels, top and bottom, are very stable even in long trains, and are thus capable of carrying mass transit capacity in all weathers. The trains can also run at grade when the line reaches the suburbs – a major advantage over most other elevated systems.
Flyda spent about $1m in the early 1980s on engineering design work on the tracks, vehicles and control system. In joint bids with leading UK civil, mechanical engineering contractors, Flyda offered systems for London Docklands and several small potential 'demonstrator' scale systems, mostly in the UK. Vancouver World Fair in Canada wanted a Flyda system but their invitation was too late to implement. Edmonton, St Paul/Minneapolis, Dallas and Houston and a number of European cities were also interested at the time.
Designs in pre-stressed post-tensioned concrete and also in steel showed that the I-beam overhead guideway could be built at about 30% of the cost of overhead structures for conventional mass transit - and with the environmental impact only of a typical footbridge. This is of great significance because, in conventional newly built urban mass transit systems, the infrastructure costs typically represent about 80% of the total cost. Therefore savings in total system costs of 70% of the 80% = 56% should be achievable from elevated guideway savings alone. The relatively small size and footprint of the elevated guideway can also be used to reduce the requirement for tunnelling towards the city centre.
Flyda systems used coupled trains of relatively small vehicles at high frequency (70 - 120 second headways) to reduce axle weight and thus further reduce infrastructure cost and to improve passenger service. Switching is from the vehicle. No moving parts are needed on the track.
In the 1980s, a control system was under development but, with the advances in computer controls, it would now be obsolete. Control systems suitable for Flyda were commercially available and presumably could be bought in now.
Flyda vehicles have wheels beneath and on top as well. When elevated on the special ultra-light guideway, they run cantilevered - left or right - from the upper and lower wheels on one side. They can also operate on the wheels underneath at grade and in tunnel. (If anyone complains that Flyda vehicles have more wheels than conventional vehicles, they should take into account that wheels are cheap, reliable and negligible in cost compared with the infrastructure savings that the Flyda technology offers.)
The vehicles also have 'track selection wheels' mounted on short pivotable arms, top and bottom at the centre line of the vehicle. At a junction these pivoted wheels engage, on the top (cantilever) or bottom (at grade), to the left or to the right of a fixed 'V' shaped member, on or above the track leading to a rail, left or right, for a few metres. For the few metres until the vehicle has passed through the junction, the vehicle is thus guided by this track selection rail, and then the vehicle re-engages with the normal running track.
At a junction the tracks will have a short gap to allow wheels to pass through. There are no moving parts on the track. Track selection is controlled simply by the position of the pivoted wheels, as instructed by the vehicle control system.
Rubber tyred versions split the load carrying and the guidance between two sets of wheels, like some lines on the Paris Metro, and otherwise operate through junctions in the same way.
Junctions sound a little complicated as the geometry is so unfamiliar. But they are simple and robust with no moving parts required on the track.
Unfortunately I no longer have a drawing of a junction but I would be happy to 'talk' through how it works with anyone interested. At the end of this document I attach simple schematics for rubber tyred vehicles operating at grade and on cantilever on which an upper track selection wheel can be seen. (The engineer, Robert Benaim, was responsible for a number of bridges on the Hong Kong Metro and has many other distinguished bridges to his name.)
Crossovers are arranged as a set of junctions analogous to a freeway crossover. One track cannot pass through another.
For high capacity, the simplest and most practical approach is to operate in long trains. High capacity is needed in the centre of the city.
But through the suburbs, less capacity is required. Less capacity is also required at night. Each Flyda vehicle has its own power and control system, even though in the city centre by day they would operate in long trains. As trains travel out from the centre less capacity is required, so trains can be split. For example a N bound train can split into a NW train and a NE train and thereafter stations can be half the size and cost. Further out, the trains can split again, until finally the last stations can be little more than bus stops at grade.
A target of one or two minute headways operating economically throughout much of the system seems completely feasible. Riders would love the frequency and budgets could be cut drastically. The absurdity of end of the line very long, expensive empty stations can be avoided!
It's the infrastructure that costs the money and creates the environmental and political impact...
Flyda mass transit technology uses entirely conventional components - wheels, motors, brakes etc, concrete, steel, etc; no magnetic levitation, air cushions or other exotic or expensive elements. It is all based on ordinary kit - wheels, motors, etc. It would be relatively cheap for a vehicle company to design. The detailed design of the unique Flyda cantilever and track features were not a problem for Flyda Ltd. It was the design costs of detailed fitting out - doors, windows, safety interlocks...etc - that proved to be much more costly than they had anticipated. A good tram, bus or minibus manufacturer would find much of this design task less burdensome.
With respect to the civil engineering, power supply and control, my experience 25+ years ago was that big civil and electrical contractors in Europe, US and Canada were very quick to join the consortia I put together for various schemes. They were confident that they could readily build anything that would be needed.
Unfortunately, Flyda was not financially robust enough to survive the extended time scales inherent in mass transit projects and slowly ran out of money and was wound up. The key elements which were patented in many countries are now in the public domain, available freely.
In the opinion of the writer this technology offers a great opportunity to urban mass transit authorities, and to civil, mechanical and electrical contractors to build and use urban mass transit systems at half or less the cost of conventional systems, with far lower environmental impact and superior passenger service. The challenge is to build the first one!
I was a Director of Flyda until about a year before its demise. I still have track and vehicle designs and the knowledge and experience which would help any large consulting engineering and/or contracting company take up and develop Flyda relatively rapidly. I believe that the Flyda technology can materially improve the quality of life for urban populations around the world at costs far more acceptable than those currently available.
I have been a Director of a leading technology transfer company for over thirty years, and am now partially retired. I believe that this technology is of outstanding significance and so I would be happy to share this knowledge with any city or companies that would like to take this technology forward.