A.E.C. Builds First Trolleybus Under Revised M.o.T, Regulations
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THE first trolleybuses to comply with the revised Ministry of Transport Regulations affecting ground clearance, are now being built for Reading Corporation by the Associated Equipment Co., Ltd., Southall, Middlesex, and the English Electric Co., Ltd., 28, Kingsway, London, W.C.2.
Without this new type of unit, the corporation, because of the low bridges in the area, would have been compelled to operate vehicles in which a reduced height had heen achieved by methods open to several objections.
Following representations to the Ministry of Transport. a special relaxation of the Regulations was granted, the effect of which was to permit the legal ground clearance of 10 ins., for a two-axle vehicle, being brought forward to a point 12 ft. 6 ins, from the front instead of the normal 14 ft. 6 ins.
This permits of the motor being moved rearwards and positioned lower down in the chassis, thus giving a B26 lower floor height. With this arrangement, the total overall height of the vehicle, over the trolley bases, is only 15 ft. 1 in.
The motor is inclined at an angle of 30 degrees to line up with the worm, which is offset to the near side, clear of the gangway.
The special 8I-in.-centre worm gear is also skewed at 30 degrees, thus permitting a straight-line drive both in plan and elevation, under average load —ensuring constant angular velocity and minimizing the working angles for the couplings.
Noteworthy improvements have been incorporated in the air-brake equipment, in which the A.E.C. patented combined reservoir and control unit is an outstanding feature. ThiS unit, which is standardized on all A.E.C. trolleybus chassis, makes for compact equipment, comprising the motor compressor and the combined reservoir and control unit. Piping is greatly gimpli
fled and the number of connections reduced to a minimum, thus reducing the possible sources of leakage. A single pipe connects the compressor delivery to the reservoir unit and from the latter one connection serves all airbrake cylinders.
Another interesting feature lies in the use of independent adjusters to all brake-camshaft levers, together with a special design of high-lift brake cam. It is possible completely to wear out the brake facings without the need for resplining the levers, whilst brake adjustment is reduced to a minimum. With the high-lift cam, one packing piece only is required during the life of the facings, which are in. thick.
These new Reading trolleybuseg, of which there are to be 25, incorporate all the latest features in design and development, and include the A.E.C. series dynamic control and battery manceuvring equipment.
They were designed to a detailed
specification prepared by Mr. J. M.
Calder, A.M.I.Mech.E., transport manager and engineer of Reading Corporation.