DOUBLE-DECK BUSES FOR NOTTINGHAM.
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A Description of Some Interesting Covered-top Vehicles for the Nottingham City Corporation.
WE have recently been able to examine some very interesting double-deck buses with covered tops which are at present under construction at the Rochester works of Short Bros., Ltd., the chassis being the well-known Dennis 48-54 seater type. These vehicles are being built for the Nottingham City Corporation and are to be six in number.
In order to give the increased stability required when the body is of the two-decker type with a covered top, the Dennis chassis has been modified in several respects, the most important change being that the track is increased from 5 ft. 6 ins. to 6 ft. 2 ins. This has been done by lengthening both front and back axles. The frame width and the disposition of the front springs remain unchanged, but the rear spring brackets have been altered so that these springs are farther apart than is normally the case.
In order to obviate the twisting stresses which would otherwise be set up by the overhang of the new spring brackets, tie-rods are provided, extending across from one to another. The springs themselves are somewhat stiffer than standard, in order to carry the increased load, and the total chassis weight is naturally greater than normal, owing to these changes.
The Chassis Employed.
The general lines of this Dennis chassis are so well known that but a brief description is required. The four-cylinder engine has a bore and stroke of 115 ram. and 150 mm. respectively, develops 4050 h.p. at normal speed, and ,transmits to a gearbox providing four forward speeds and a reverse. The drive is then taken by an enclosed propeller shaft to a sturdy built-up back axle, enclosing an overhead worm drive. In the ease of the double-deck buses the tyres used are 140 ram. by SS1 mm.
twins being employed on the rear wheels.
A particularly large petrol tank is fitted, the capacity of which is 411 gallons, and this is carried amidships, with a large filling orifice extending to the off side of the frame. The silencer is carried just in front of the back axle, with an outlet pipe directing the exhaust transversely towards the centre of the chassis.
Details of the Bodywork.
Turning to the hodtywork, this is constructed on the Flitch principle, and the combination of lightness and strength obtained is an excellent tribute to the experience and workmanship of Messrs. Short Brothers. The total seating capacity is for 50 persons, made up of 22 in the lower -saloon, 26 in the upper saloon, and two in the driver's cab:.
A feature of the method of construction adopted is that the upper and lower saloons are completely built up as two independent units, and are only put together after all the glazing and similar work has been completed. We watched the assembling process being carried out, and were impressed by the way in whigia all the numerous joints fitted together without trouble, showing how completely the work is jigged in the process of manufacture. The upper saloon was simply raised by a crane and dropped upon the projecting pillars of the lower saloon, every joint fitting with the precision of a machine-Shop job. The lower saloon has two longitudinal seats just within the entrance, each seating three passengers, the remaining accommodation consisting of four transverse seats on each side of the gangway. The width is 6 ft. 10 ins, at the seat line and 7 ft. 4 ins. over the mouldings. From the floor to the underside of the hoop sticks measures 6 ft. The pillars, waist rails, cant rails, body framing etc., are all of ash and the floor consists of pine
tongued and grooved, which is secured by screws to the sole beams and cross-members. Hardwood Slats are fitted between the seats and along the gangway. The lower saloon is panelled with 7 runt three-ply, the joints being covered by metal strips, and the panelling of the upper saloon is similar, but only 5 ram. in thickness.
The rear platform is framed with ash reinforced by angle plates and is covered with deal boards, on which hardwood slats are fixed ; stanchions are used to carry the aluminium dashplate in tbe usual way. The upper saloon is provided with seven transverse seats to the left and six to the right, each accommodating two persons, which are slightly staggered to assist easy entry and egress. The hoop sticks of both lower and upper saloons are of ash reinforced with flitch plates, triangular gusset plates being employed to stiffen the joints between these and the pillars.
The roof of the upper saloon is formed of two layers, with a waterproof covering between them. These layers consist of birch on the inside and three-ply on the outside, while tin curved front and rear ends of the roof are beaten out of 16 S.W.G. aluminium sheeting. All the transverse seats are built up on light frames and are provided with loose cushions, the backs being fitted with padded shoulder rests. The longitudinal seats in the low saloon have similar loose spring cushions, together, with fixed squabs, upholstered to match the transverse seats.
The lighting of both saloons is excellent; OWing to the large window space provided, and, in the upper part, three windows on each side are arranged to slide in felt-lined channels controlled by window lifts. In the lower saloon hinged ventilators are employed on each side above the windows.
As will be seen from the photographs, the upper saloon projects over the driver's cab, and the headroom afforded is as good as can be expected in vehicles of this type, the height from floor to roof inside being actually 5 ft. I3j ins., while the overall height of the bus is slightly more than 14 ft.