Steel Double-deckers.
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A Description of the Most Recent Practice in Motorbus Body Construction.
Judging by the similarity in appearance of most of the buses running on the London streets and elsewhere, there is practically only one idea in respect. of outline among their designers and builders. This is probably due to the restrictions of Scotland Yard for London—and the others follow suit. The Metropolitan weight limit, of 3 tons 10 cwt. for the complete vehicle, does not leave much for the body-builder, after 2 tons 10 cwt. are taken for the chassis. The body nowadays ha.s to be crowded with all sorts of etceteras, all to come within the other 20 cwt. Outside of the Metropolitan area, this limit is not so rigidly observed, but the weight has to be kept down to save tires, petrol, and other running expenses.
The weight thus allowed does not give much scope for studying comfort, effect, stability, and, in connec tion with the latter, low cost. of upkeep. Builders of wooden bodies have had their capabilities taxed to the utmost, to get within the weight and yet to observe all the other regulations that are imposed.
The bodies which are now in general use are of limited proportions, they are very light and very narrow. It is a difficult matter for more than one person to land on the rear platform of the London motorbus at any one time, and to find a way inside without treading on everybody else's toes whilst desperately strap-hanging. The seats do not allow any too lunch room and comfort is not of primary importance so long as the regulations are observed. The two conditions unfortunately are not synonymous. One usually has to ascend sideways to the top of a double-decker by a stairway, similar to that in a lighthouse, unless there "is no sideways," as was evidently the ease of the rather fat passenger in the tram who, when asked to sit close up or edgeways replied that she had no edges. Again, the seating on the top is none too ample-as a rule there is far too little knee room.
As mentioned at the commencement of the present article these drawbacks are due primarily to the official restrictions placed upon the buses; they have not yielded sufficient scope for building a body on the old lines sufficiently strong and stable to meet modern requirements. There are a few exceptions, however, to this development or lack of it as to every rule. The L.G.O.C. has some running and is placing many more of a new type on the road, some with cross seats ; these are BO much more artistic and symmetrical in design than the square box type with which we are so familiar. •
There is a new type of bus body to which however the writer wishes to call attention ; it is one which has lately been produced by the Daimler Co. at its workEi, from designs by Mr. E. Hewer of Leamington. Art illustration herewith gives a good idea of the general design, which is not dissimilar to the latest ones to be seen on the London streets. It has only to be placed alongside of one of the ordinary box type of bodies for the striking difference to be seen.
All the dimensions are to Scotland Yard regulathms, where these are specified, but where latitude is allowed full advantage of this has been taken. This is particularly noticeable in the full unbroken side and under sweep which allows 3 ins. to 10 more room inside than is available in the ordinary type.
The great departure from the orthodox is, however, in the construction, and it is quite worthy of Daimler methods. The whole framework is of steel, very light but having an unbroken line from hand-rail to chassis ; connection is made across the bottom_ and the roof by steel tie-bars, The shape of the cross-section is on the lines of a tunnel and is, so far as is possible in so light a structure, proof against distortion.
To the side steel members. inside steel plates of a, very light gauge are riveted, forming the sides into, deep girders. The panel on the outside is aluminium screwed on in small sections—an appearance panel only, and one that is easily renewed. The windows as shown are frameless, bedded in on rubber or felt, and kept in place by a, wooden bead, easily removable these lights can by the same method be framed sci as to allow the vehicle to be used as an open car for hot countries if desired.
The ventilation, as will be noticed, is of an induced description and cannot be interfered with by inside passengers. When the vehicle travels forward the air is scooped up and taken inside, when, instead of journeying down the necks of people, it is carried by: baffle plates to the centre of the body. The roof itself is built up as a separate component ; indeed the whole body is designed so that it can be built in sections and assembled afterwards if required.
To use steel in the framework and panels, each part has to serve some purpose in itself and assist others, the whole scheme of construction being scientific ; this has to be, in order to get the great strength which is obtained with the lowest possible weight. This is strikingly e.xentptified in the roof, which is under compression in such a way that it is doubly a weight-resisting structure ; it has a slight spring, and becomes more steady and firm as the weight is increased.
The top-deck seating is ample ; the seats, of the small-lath type, built up on a steel frame, are attached to the roof and the side-guard rails and act as a support to both. The hand-rail is of the tubular description and is built in as part of the framing. A stairway 18 ins, wide is provided at. the rear, and a platform of ample dimensions is available. In the illustration it will be noticed that the driver's comfort has been carefully considered, but on the buses. in the Metropolitan area, no part of the body, except the roof, is now allowed to extend beyond the cross end. The inside cross seating is exceedingly comfortable, and a long ride can be taken in this body, with as little inconvenience as in a railway coach. The cushions are manufactured by the Lace Web Co.
This bus as a whole is unique, it marks a new era in construction, and one which should be appreciated by the builders, owners, and users. As it stands in the photograph it has just returned from a three months service trial. For foreign traffic, and for colonial work, where this type of double-decker and also the single-deck car is used, it should be in much request, as repairs and upkeep are by the nature of its construction likely to be reyduced to the minimum.
For standardized and special types. arrangements have been made with Mulliners, of Birmingham, to supply complete sets of parts ready for asserribl1pg.