The Garrett Electric.
Page 9
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First Example of a New Chassis Makes Good in Norwich.
The spread of a real understanding as to the limits of the electric vehicle is operating greatly towards increasing the success of that vehicle. One particular direction, in which its utility is apparent is in the distribution of goods by the railway companies in large towns. It is perhaps in this sphere, and in connection with municipal operation, that the greatest expansion of the use of this type of transport vehicle may be expected. The Midland Railway Co., .as.is well known, has invested largely in the. electric, and is continually increasing the number of these vehicles which it has in use. It is of interest to.learn That the Great Eastern Railway Co. is now experimenting on similar lines, particularly so since this company has taken as its first choice a vehicle made by that wellknown British .concern, Richard Garrett and Sons, Ltd., of Leiston.
We were happily able to preface our technical examination of the Garrett chassis by a meeting with Mr. W. H. Hall; the divisional -commercial superintendent of the Groat Eastern Railway at Norwich. This gentleman is, we believe, responsible for the intreduction of the electric into the Great Eastern Company's transport arrangements: He favoured us with a few particulars as to costs of running and his experiences as gained during the term of six weeks for which the vehicle has loeen in Commission. Naturally. during such a short period all-in costs are not available. For the purposes of . comparison, he has, however, taken certain figures supplied to him by the maker for the items of depreciation, repair, etc. We hafe gone into these figures in detail, and-find ourselves inagreement with them on general grounds. Those referring to the battery have been calculated in the same manner as the corresponding figure for the tires. A period of life is guaranteed for the battery, and it is on_ this that the depreciation has been calculated. We saw figures showing the work performed by this vehicle, the loads carried, and other items of importance, as well as the net cost per 'ton carried. From these we have extracted the important items concerning the running during 22 working days : 307 tons were carried on 100 journeys, during which 965 deliveries of goods were made, the actual time during which the vehicle was working being 245 hours. The cost of running, including current, maintenance, depreciation, interest on capital, insurance, and•items for replacement in due time of batteries and tires, was 215 8s. The amount
of wages, bonus, etc.. to driverand anale amounted in round figures to £14. It will be seen that the cost per ton carried was Is. 11d. This vehicle actually displaces three single-horse vehicles, and it is estimated that on a similar basis the cost by horse transport would have been 2s. 8.8d. The saving is thus shown to be 9.8d, per ton carried.
A few ibrief particulars of the ichassiii itself may now be given. In general design it does not in any way depart from customary practice in connection with electric chassis. A completely enclosed
motor. is carried transversely, just in front of the rear axle. This
motor drives by silent chain, which is also completely enclosed, and which runs in an oil-bath, to a ferential cross-shaft. The final drive from cross-shaft to rear axle is by means of a pair of roller chains, one at each side. The battery is carried under the chassis, immediately behind the . driver's seat ; the control is by a leiter working in a horizontal quadrant on the steering column.
Although,. as we have stated there is nothing in the general de sign to distinguish this vehicle frOni others, there are, as might natur ally be ekpected in anything emanating from' a concern like that Of Richard .Garrett and Sons, Ltd., several features of the design which should make for efficient and economical running. Perhaps the most important of these is that inconnection with the control. This embodies a patented Garrett fea ture, which was described by us on the 15th March last. It will only be necessary to remind our readers that this device operates automatically to cut off the current from the batteries immediately the driver commences to apply the brake; similarly, it is impossible for the driver to attempt to start without first removing the brake.
Another notable feature is in connection with the suspension of the differential cross-shaft, this being carried at each end by spherical bearings, the object 'being to obviate any tendency to strain the shaft as a result of occasional twisting of the frame.
The particular chassis employed by the railway company has a capacity of 3+, tons. it is designed to be capable of travelling from 35 to 40 miles upon one charge of a battery, at an average speed of eight to nine miles per hen". A smaller size is also included in Garrett's programme with a capacity of 21 tons. The Ironclad-Exide battery is fitted, being carried, as we have stated,'-below tlae chassis frame, in trays conveniently ,arrangecit both for size and position so that they can be withdrawn from either side of the -vehicle with ease. The 8 hip. motor has a 300 per cent. overload capacity.
Both the brakes take effect on drums on the hind wheels. The controller allows of six speeds forward
and four reverse. Special attention has been paid to the lubricaticm, anti ban or roller bearings are fitted throughout.