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Title: Dunlop's easy rider

Pages: 76 - 79

            

Author: David Rowlands

Text: 
DUNLOP'S EASY RIDER
A prototype Dunlop Speedaway moving pavement is on trial at the Battelle Institute, Geneva, where the design of an accelerating Integrator was first proposed. David Rowlands describes the system and asks whether this is the right solution to people movement in cities.
Expo 70 at Osaka provided a salutary lesson to the protagonists of moving pavements. The rubber belts, forming 276 metres of pavement, gave millions of passengers impressive views of the exhibition site after initial crowd problems. But two vital questions have to be resolved before Dunlop speed the belt up from its sedate 3 kmh to the 15 kmh system now on extensive trial at the Battelle Institute, Geneva. One is safety and may be considered as a combination of mechanical and user education problems; the other, which may prove the more difficult, is integrating moving pavements and their supporting and enclosing structures into the fabric of urban transport.
Speedaway is a combination of the familiar ribbed rubber moving belt Starglide system and the Integrator, a pavement of moving aluminium treads having a peculiar geometry that permits access at walking pace and gentle acceleration up to 12 kmh. The belt can be used alone, as at Osaka, or with the Integrator to speed passengers up to a forward velocity at which they can transfer safely to a belt moving at 15 kmh. Additionally the Integrator by itself, designated Speedaway S, is practical for distances up to 200 metres. Belts can be curved very slightly to accommodate small deviations in the line of travel, but Speedaway S can only be stepped into a parallel course and that at loss of speed and passenger separation. Both belt and Integrator can go up small slopes - up to 15 with the Starglide but rather less with Speedaway S.
Starglide handles up to 7200 passengers per hour, the full Speedaway system 30,000 per hour, and Speedaway S falls between them at about 10,000 per hour. Both belts and Integrator are reversible - Speedaway S is particularly suitable for peak flow reversal if three pavements are installed.
Drive is all-electric. At the slow speed ends of the Integrator or S system, electric motors with reduction gear boxes drive scroll cams accurately locating each parallelogram shaped platform at the entry and exit point. These are followed by the accelerating section through a parabolic path where the platforms slide and lock together to form the continuous pavement. This stage is driven by linear electric motors which act as brakes if the current is reversed. Main high-speed belt drive is by rubber-tyred friction sets. Dunlop claim that noise is very little problem because the rubber components damp out vibrations. Each Integrator platform is cut from an extruded aluminium section and the comb plates, mounted centrally on the platform, are an extrusion also. The comb plates perform two functions: preventing shoes being trapped at entry and exit points and cleaning out the dirt or debris that may clog the lock and slide mechanism. To some passengers they may also provide the security of a fixed reference point on the platforms while all about them moves. The platform's shape is dictated by the need to form a straight edge at the point where Integrator meets the main belt.
Speedaway is very much a joint effort, with impetus from NRDC and Dunlop and engineering ability brought to bear by Battelle where the prototype system is running. The Integrator stems directly from an original Battelle patented design.
The prototype is 33 metres long by 16 metres wide - a full Integrator and a curtailed high speed belt. Moving handrails are not provided although they would be on an installed system. The trials include continuous running to check wear and reliability, passenger reactions from a varied sample of Swiss citizens (some bring along the kids and pushchairs and make a day of it), and power requirements and heat generation are measured.
Dunlop's research includes studies of Speedaway applied to three urban transport schemes. In London the possibility exists of linking north and south banks of the Thames by a Speedaway across London Bridge which could be extended north to Liverpool Street and Broad Street stations. A scheme under discussion in Liverpool is a little more ambitious. There the system could meet two needs; a park and ride link between two large 5000 car parks on the edge of the city's motorway box, now under construction, and a transportation system along a pedestrian precinct which will cross the central area. The third study, and the one most likely to materialise, is for a three stage movement system along the main elevated boulevard of La Defense, the new business, shopping and residential centre under construction close to the centre of Paris. The Paris project is now entering its second stage in which Dunlop together with consultant architect Brian Richards and consulting engineers Ove Arup & Partners and Jean Prouve have been asked to consider the development of an initial flexible system. Cautiously the Paris Authority, EPAD, may go for a walkway/ Starglide/Speedaway S combination to try out initial reactions, although the full Dunlop recommendation is for three parallel Speedaway S systems over the central stage plus two- and three-pavement systems for the other stages.
The architect's dream of a glass people-tube as half carried out at Osaka and more recently the Dusseldorf fairground isn't on in the more prosaic world of urban transport according to Brian Richards. Solar heat gain, only just reduced to bearable levels at Osaka by packaged air-conditioning plant and refrigerated panels throughout the tubes, presents insuperable problems. Glass, especially bent glass, is expensive (it must be of armour plating grade) and plastics like Makrolon need constant cleaning to overcome electrostatic dust attraction. The La Defense solution is an air-conditioned tube with large outward sloping windows to avoid internal reflections at night. Plastics are ruled out on fire safety grounds so the structure is panelled in stainless steel sheet. The roof is light enough to be supported on the widely spaced mullions. Height above ground will be around the 2- metre mark which allows free access under the tube but still gives pedestrians some shelter. Support piles will be of steel, placed 33 metres apart. The bulky profile allows space for an engineers' cat walk.
It is all very well to point to La Defense and say that Speedaway integrates very well with the surrounding architecture but this is a design where some method of transport was envisaged from inception. Cafes

(Caption page 77) The Integrator, below, accelerates pedestrians to a safe speed for transfer to a fast belt, diagram left, it can also be used alone for short distances (up to 200m ). Osaka's Starglide installation, opposite, revealed the problems Dunlop consultant architect Brian Richards, faces in translating moving pavements to Liverpool's proposed precinct above.

(Captions page 78) Dunlop's Speedaway applications research has covered a proposed link between commuter
train terminals north and south of the Thames. Photomontages, right and opposite, show the Speedaway crossing the new London Bridge.
The first Speedaway S installed may be in La Defense, Paris. Engineers Ove Arup & Partners and Jean Prouve with Brian Richards envisage a three stage installation, plan below. The steel panelled structure, section right with armoured glass windows will provide an umbrella for cafes and kiosks.


will flourish under the shade of its roof and the usual idyllic artist's drawings show the tube wending through the leaves of trees planted in tubs on the deck. Liverpool presents the sort of system that could emerge elsewhere in Britain - a new mode of transport superimposed upon the architectural patterns of a bygone age. A full Speedaway system is like a mini-motorway - it has interchanges wherever access is required to the high speed belt. If it is to compete with, say, minibuses these must be every 200 metres or so. A sort of clover leaf junction arises - two Integrators parallel with two belts all at whatever height is necessary to preserve freedom of movement underneath. It represents a lot of blocked light and large-scale visual intrusion.
The same argument is levelled against developments like Cabtrack and here the immediate reaction was to suggest cantilevering the system out from existing fabric. The future held no drawbacks - buildings would have rights of way built into them. Speedaway differs from Cabtrack in that it cannot conform to an existing fabric: it must go in a straight line. Architectural spirits have been dampened by a realisation of the additional parameter of conformity this would impose and the daunting problems of co-ordinating the construction of such a system. There is a feeling that Speedaway S presents a more acceptable possibility. Passengers have to alight every so often and can more easily orientate themselves whereas they might miss their stop on a fast belt, and the variable stage lengths could be set at angles to fit any given route - a fast belt system has to be virtually straight.
What are the safety problems? One was highlighted at Osaka where 42 people were injured in a pile up at 3 kmh. The fact that this happened at all was blamed on excitable Japanese temperament and unfamiliarity but even the possibility of a passenger block at 15 kmh must be eliminated. Dunlop see this as a question of education and common courtesy - barging past the aged, infirm or plain slow is bad manners when you're travelling at that speed, anyway. The pavements are narrow to keep passengers in line ahead without passing but they have to be wide enough to cope with pushchairs and luggage, so the possibility of people pushing by cannot be totally excluded.
If an accident did happen there would have to be an emergency stop. Pulling up suddenly from 15 kmh could cause more injury again. So a fine balance of braking power against the possibility of creating serious injuries must be struck. Escalators provide most of the safety parallels one can think of and even on latest types the comb plates can still trap the stiletto heel shoe. Dunlop's comb plate design is profiled so that anything jammed in the teeth, either when the Integrator platforms slide against one another or at the entry or exit points, is squeezed out. But it will take a good deal of experience to prove to passengers that this is true.
Fire presents a different hazard in the conditions of an enclosed tube. At Osaka the solution was emergency exit stairways at intervals and this is favoured by Paris fire prevention officers. Brian Richards investigated various ladders and chutes for emergency use but they all had the disadvantage of destroying the tube's visual impact and, in the case of stairs, obstructing outside cleaning of the tube by remote-controlled machine. The latest design of tube has walkways either side of the Speedaway S pavements which will perhaps be acceptable as emergency exits although they are primarily for maintenance workers. It is interesting to note that Liverpool fire prevention officers banned the use of aluminium panelling on grounds of insufficient fire resistance.
The remaining problem Dunlop have to solve is that of accelerating the handrail at entry and exit points. Without a handrail synchronised to the movement of the people on the speeding platforms it is difficult to see how passengers could manage the transition safely. Dunlop admit that this is causing problems but are confident they will be solved by the time the first production Speedaway is installed - 1974-5.
Speedaway is a serious proposal to solve the problems of short distance urban transport. It can work in situations where there is a consistently high flow of passengers over a distance greater than half a mile. There is no doubt that something like it must be found acceptable if the car and ultimately the bus are to be banished from city streets entirely. Architecturally it will need a very sensitive hand to prevent Speedaway becoming the latest in a long line of menaces to the built environment.

 

 

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