COMMERCIAL MOTOR
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Officially Recognized by The Commercial Motor Users Association.
The Authority on all forms of Motor Transport. Largest Circulation.
Conducted by EDMUND DANGERFIELD. Editor: EDWARD S. SHRAPNELL-SMITH.
The Skidding Controversy: More Data Essential to its Settlement.
it is seldom that we find ourselves at issue with the editor of our contemporary, "The Surveyor." We are obliged to disagree, and to do so very emphatiealiy, in respect of that expert's recent declaratioa that the skidding and sideslip of motorbuses are more due to unsuitable wheel and tire dimensions than to excessive angles of crossfall in street construction.
further point, to the effect that the brakes of Lon(loll motorbuses are of defective design, is one which will no doubt receive attention at the hands of the I-G.O.C. We have not the advantage of knowing why our contemporary writes so about the brakes, and we seriously question its being more than a casual assertion. It is, none the less, a. hsrmful one.
The writer made an effort, in the month of April, 1907, on the occasion of a conference between roadmakers and road-users, which was organized by the above-mentioned journal at Olympia., to secure data bearing on the problem of adhesion between rubber and different road-surfacing materials under varying atmospheric and traffic conditions. it was not an easy task, because such data appeared to be virtually eon-existent, but we may very properly go hack to the theme somewhat briefly.
The co-efficient of friction for rubber-tired driving wheels on dry macadam has been shown to be as high ala 0.68, which is equivalent to a. limiting angle of friction of 30 degrees, or to a gradient of 1 in 1.72: it falls, on greasy asphalt, as low as 0.06, which is equivalent to a limiting angle of friction of three-and-a-half degrees, or to a gradient of 1 in 16. The following 1.,;; hie was included in the paper which we mention:— APPROXIMATE SCALE SHOWING TENDENCY OF THE SMOOTH, P :11fIER-TIRED WHEELS OF A, MOTORBUS TO SKID AS ADHESION IS DIMINISHED.
We have recently made inquiry, in order to ascertain if more-recent data have been compiled, and we are surprised to find that nothing of the kind is available. We venture to commend to the directors of the L.G.O.C. the expediency of their undertaking a series of investigations in the laboratory of the Walthamstow works of their allies, the Associated Equipments Co., Ltd. The seriousness of the conditions when wet and greasy asphalt occurs in conjunction with an excessive angle of sidefall to the channel is undoubted. Whilst asphalt should never be laid with an angle of 841001 exceeding 1 in 30, we have ourselves in past years measured many angles steeper than 1 in 13, and some of our supporters may recall that we had attention drawn to the matter in the House of Commons. The Holborn Borough Council thereafter flattened considerable lengths of Oxford Street, east of the Tottenham Court Road, but angles steeper than 1 in 30 can still be found in abundance in London thoroughfares, and we maintain that these are dangerous. The driver of a motorbus is left to perform a. number of balancing feats, in order to secure the forward progression of his vehicle.
It is necessary, having regard to the demand upon the adhesion limit of the driving tires of any motorbus, to recall, when considering this problem, that from 0.025 to 0.03 of any co-efficient of friction is exhausted for propulsive purposes. Seeing that the coefficient of friction is only .06 upon greasy asphalt, little if any margin between requisite adhesion and maximum available adhesion is left on a gradient or crossfall steeper than 1 in 30.
Driver-ownership of Taxicabs : Attitude Towards Fare Increases.
We gather, as we had anticipated, that all is not well with owner-drivers of London taxicabs. Men who have in past years abused the advantages of driving vehicles which belonged to other people, and have made minimum returns to the owners out of the gross receipts that came their way each day, are the chief sufferers, and possibly there will be very little sympathy for them. The best types of owner-drivers will not fail to obtain better results than those which are troubling the less-worthy ones.
We are particularly informed that some of the men who hastily became owner-drivers, before they appreciated that ownership brought with it new responsibilities, have suffered in respect of certain classes of claims against which it is not easy to insure with the first of every mishap or loss covered by the policy. They are, perhaps, finding their new experiences of salutary effect., and we trust that they, in these new circumstances, do not still think harshly of their former employers. They at least are conscious of the difference of having no high-speed-repair organization, which at one time was at their call and disposal, to help themlout. The records of London taxicab operation will continue to show an increasing percentage of driverowners, and the recent unfavourable report of the Gamage-Bell undertaking is but another indication of the parlous state to which Proprietary owners haVe been¼ reduced by force of circumstances which are almost entirely outside their own control. Successive concessions have been granted to the drivers, both by the Government and by the men's employers, contrary to the best judgment of the latter. When the situation is reached that half the men are their own employers, we believe that their-eyes will be wider open than they are at the moment to facts as they exist. It is difficult to estimate the nature of the outcry that will then he raised but we do look forward to insistence upon a higher scale of fares for the Metropolitan police area. When the driver took 51d. -out of each short-distance hiring, subject to an outgo of not more than !,d. for petrol, and when he had not fewer than 12 such hirings a day, the very fact of his being a driver, and not a driver-owner, caused him to range himself in opposition to any increase of the initial charge. We prophesy that his old attitude will be reversed before very long, but that change will, unfortunately, be too late to avail the original or reconstructed companies to the extent which their efforts as pioneers undoubtedly merit.
Roads Under Heavy Motor Traffic.
London ratepayers generally are indebted to Mr. J. C. Mitchell, a member of the Lambeth Borough Council and treasurer of the London Electric Railways, for the manner in which he has been fighting the cause of motorbus and other motor traffic of late. Mr. Mitchell has already succeeded in shaking the old beliefs of the Lambeth Council to their foundations, and that was certainly no easy matter, so deeply-rooted were the convictions of certain members in respect of relative costs of road maintenance under horse traffic and motor traffic.
Many readers Of TILE COHMERCIAL MOTOn may be unaware of some of the data which Mr. Mitchell put forward, and we therefore now refer to sonic of them. He has pointed out that, comparing the horse-drawntraffic period of 1905-1906 with the motor-traffic period of 1911-1912, the following decreases in annual costs per mile of roadway, for cleansing and scavenging, were shown in the following six London Boroughs : Battersea and Chelsea, decreases of .2108 per mile; Fulham, adecrease of 2106 per mile ; Paddington, a decrease of 2124 per mile ; Wandsworth, a. decrease of C91 per mile ;, -Westminster, a decrease of 2179 per mile. Several other London Boroughs show decreases, and only five show increases, but in these five there are special explanations, due tochanges of system.
A particular case of saving on maintenance, into which we have ourselves inquired with care, concerns the roadway known as Castelnau, which roadway connects the south side of Hammersmith Bridge with Barnes. This was a macadam road, prior to the year 1007, and it went to pieces under motorbus traffic. The noise due to the baeP surface was considerable, and the inconvenience to bus passengers, as well as to residents, was admitted on all hands. The Barnes U.D.C. spent 29500 in relaying the 71i furlongs of roadway with woad paving. This figure is a complete one, including charges for excavation, foundations, and everything necessary ; it works out at 9s. 8W. per superficial yard. What has the result been, from the standpoint of economy ?
We find that the cost of repairs to Castelnau, in its days of macadam construction, was .21149 178. 7d. for 1906 and .t38:3 148. 8d for a portion of 1907. The conversion to wood paving was finished hi October of the latter year, and, since thatdate, with the exception of a few minor alterations due to the opening out of new roads into Castelnau, and a few modifications of sewer, water or gas connections, no repairs whatever have had to he done to the read. There has not been a single repair because of the motorbus traffic : not 1d. has been spent on that account. Thus, after nearly 6!-; years of service under concentrated motorbus traffic, the action of the Council's engineer, Mr. a Bruce Tomes, in making a suitable road has been thoroughly justified. Needless to say, the former noisiness disappeared with the relaying.
The moral clearly is, to lay the right kind of roadway. This need not always bewood paving ; it may in many eases be asphalt-macadam, in view of morerecent experience. It is appropriate road mainte.nanen that saves money for the ratepayers, whereas unintelligent, retention or repetition of out-of-date methods are hurtful both to the motor industry and the local rates.
Electricity or Petrol ?—Berlin Cabs.
A short memorandum, from our own correspondent in Berlin, will be found here below. This note briefly summarizes the present situation in Berlin with regard to the degrees of esteem in which petrol-driven and electrically-driven taxicabs are respectively held by the hiring fiublie.We have ourselves tried both types of vehicles during visits to Berlin, and have found them equally serviceable in many respects, with the advantageof higher point-to-point speed on the side of the petrol-driven examples. With regard to noise, we readily agree that certain petrol-driven cabs which were on the streets of Berlin five or six years ago did not run very quietly, but that con, comibint has been subdued more recently.
The electric cab, nowadays, has but little chance of securing public favour by reasons of claims which are based upon alleged superiority in respect of the degree of noise or absence of smell. There are too many petrol-driven vehicles in the streets of any capital city for the introduction of a proportion of electrically-driven types to affect the total result, quite apart from the fact that ignition and combustion are both achieved in virtually perfe-ct fashion, which certainly was not the ease some years ago. The -electric vehicle scores only when the driver element is below the average.
The new order of Herr Von Jagow, the chief of the Berlin police, under which licencees of electric cabs will in. future have to surrender two horse-ca-b licences. for each electrie-vehiele licence, will probably remove the incentive that has enabled Berlin to show an increase of 201 electric cabs for the period 1913-1914, compared with a contemporary increase of only 44 petrol cabs.
Von Jagow, Berlin's President of Police, has discovered that his policy of licensing new petrol-driven cabs on condition that the licences of 10 horse-cabs be cancelled, and of placing no numerical restrictions whatever on the working of electric cabs, has resulted in an extraordinary increase of the latter, both relative and positive. This rate of expansion is, in the president, s opinion, quite inconsistent with the needs of Gross-Berlin, and he has consequently issued an order to the effect that, henceforth, no more electric cabs shall be licensed unless the applicant can offer two horse-cab licences in exchange.
We give the relative figures since 1910, supplied, upon my own special application, by the Berlin Street Traffic Department.
*About this time the electric-cab traffic underwent a set-back through the financial difficulties of the leading working company.
It will be noted that the electric type, the bulk of which„ by the way, are N.A.G.s, showed an increase of 201 vehicles, compared with one of 41 in respect of the petrol variety, during 1913. Handicapped by the 10-to-1 ratio mentioned above, the " petrols" have increased but slowly ; as a matter of fact, the statistics quoted show that in 5 years only 339 have been added to the general stock. Arguing on these figures and those relating to the electric cabs alone, one might infer that the number of horse-cabs has undergone no striking diminution during the same period. This is really the case. Von Jagow's policy is to bring about a very gradual decreaso of horsecabs on socio-economical grounds. There are still over 3000 horse-cabs licensed in Berlin.