Dolter Stud Contact System

DOLTER STUD SYSTEM

Under the heading “The Dangers of electro-Magnetism for Tramways.”  ‘The street,’ an illustrated weekly journal published in London, has some remarks of very considerable interest to Hastings.

We cannot find space to reproduce the whole article, but we may state that it opens with a declaration that the early defects in general of the electro-magnetic systems of traction “still remain to be overcome, and as these defects involve unreliability and possible danger to the public, until they are removed such systems are not, in our opinion, adaptable to public requirements.”

Then follows a description of the Lorain system, which has now been at work at Wolverhampton for four years, and in the course of the remarks on this subject the statement is made that the “live” stud difficulty “apparently remains the irremediable defect of the electro-magnetic systems.

Next the Dolter system is dealt with, and as this has been adopted for Hastings we publish this part of the article in full.  It commences under a sub-title, “The Fallacy of the ‘Earthed Skate,” and is as follows:-

We would quote from an article, which appeared in ‘Engineering’ for November 21st 1902, written by Mr. G. Paul, of Nuremburg.  He said:- ‘As a means of safety with the Dolter system of surface contact, both ends of the car are fitted with an earth skate, which strikes on each stud short circuiting it, should it have remained alive, the short circuit causing the fuse in the surface contact to melt.  One would assume that by this means the safe working of the system would be insured; on further consideration, however, it is easy to see that such a contrivance

INTERFERES WITH THE PROPER WORKING

of the system, and tends to reduce, rather than to increase, its safety as far as road traffic is concerned.  Thus supposing that a stud has remained alive from one cause or another, and that the earthed skate strikes it, producing a short circuit, it is not proved that the fuse would melt; the time during which the earthed skate is over he stud is so very small that the fuse may fail to go, unless it is designed to “blow” with a very small current excess.  In this case, however, it will be liable to go when the current intensity is a high one; in starting the cars, for instance, or over heavy gradients.

There is also the danger that the earthed skate may not perform its function, the stud keeping alive notwithstanding, while the arc between both carbon contact remains in spite of the magnetic blowout fitted to the movable lever of the contact apparatus.

It is generally assumed that the surface contact apparatus works sparklessly, as one of them is already under current before the other is cut out.  In practice, however, this has been shown to be no more that a supposition, for notwithstanding the most careful insulation of the street contacts, there are small amounts of current flowing to earth; there are also at times current losses by leakage, this being especially the case in winter, when salt is resorted to in order to clear the track from snow.  It is always asserted, with reference to the Dolter system and all other similar systems that the stud is always cut out immediately the collecting skate on the car has left it.  Experience, however, has shown that when a leakage occurs from the studs to the rails the contacts in the apparatus open out but slowly and sparking occurs to the residual magnetic flux.’

Now the advocates of the Dolter system in this country are basing their claims on the experience gained from a short length of line laid on the outskirts of Paris.  Of what value that is for proving it to be a thoroughly reliable system of traction, suitable for use in English towns, we may gather from

FEW ENLIGHTENING FACTS

they will, at least, show on what slight evidence English Municipal authorities grant the privileges of their streets.

The Dolter system forms the central part of the line running from Port Maillot over the Pont Surennes; the line is constructed on a strip of ground divided from the main roadway, and is not transverse by the ordinary traffic of the street.  In the first place, therefore, the line is not laid in the City of Paris, and is not subject to the conditions of ordinary horse and vehicular traffic.  Moreover, although it has been running for five years outside the City, the authorities have never agreed to its being introduced into the busy streets of the City itself.  A short track on this same system has also been laid down outside Dresden, which is supposed to contain certain improvements in the studs, but as it has not been taken up by the Paris authorities it may legitimately be concluded that it is no better than on the Paris section.

“Even with all the experience of these systems before one, therefore, it certainly appears premature to give such wholesale authority until one line at least had been installed and satisfactorily worked.

Surely no matter of such vital importance as the selection of a tramway system has been decided on such

SLENDER AND UNSATISFACTORY

RECOMMENDATIONS.

Had these Continental enterprises been successful, and had they proved that the system was one which could without doubt be adopted by English authorities, had it obtained a record of indisputable success, had it proved itself an advance on its predecessors in the matter of refractory studs and other points, then we should have gladly welcomed it as a worthy and much-to-be-preferred successor to the overhead system.

Another magnetic system which is at work in Paris itself is that known as the Diatto, of which the Dolter is presumed to be an improvement, although the older system has been adopted by the City proper, while the newer one still remains out in the cold.  If there is anything in analogy then the Dolter systems does not come out in a very favourable system, does not some out in a very favourable light.  From the report made by the Prefect of Police of Paris, we find that between June 5th 1900, and February 20th 1901, no less that 120 accidents due to live studs occurred.  Steps were taken with the object of endeavouring to get rid of these difficulties, but in an article in ‘Engineering’ in November 1902, the writer commented on the fact that the safety device placed on the car  of the Diatto system has been dispensed with, and remarking that it was ‘not easy to understand why a safety device should be considered superfluous, as the numerous accidents which occurred until very lately, in Paris, with the said system safety should have afforded a proof that efficient should have afforded a proof that efficient safety appliances cannot be dispensed with in such a surface contact system.’ “

HAS THE COUNCIL BEEN TOO HASTY

The action of the Hastings Town Council in accepting the Dolter System is criticised in the following letter, which was crowded out of our issue of Saturday last:-

To the Editor.

Sir,   You kindly inserted a letter from me a fortnight ago; will you allow me to say I was not aware then, that the question of deciding on a system of trams for the Front was to be settled so precipitately, and, moreover, against the opinion and in the absence of the Borough Engineer, owing to illness?  However, it is not the first time the town has been given away, and I suppose it will not be the last!

All the 21 amateur engineers who voted for the Dolter system are evidently for trams at any price!  Not one of them knows anything about the question, which is purely a technical one.  Surely the Corporation have had ample time during the past six months to obtain advice from some of the best known tramway and electrical engineering experts procurable, even if it cost the town a thousand pounds or more.

Why did they not take up the threat of the Tramways Company and go to the Board of Trade, when the whole question would have been thrashed out and settled to the satisfaction of the town?

The Tramways Company Directors only in November last wrote to the Tramways Committee of the Council: “We are convinced, as the result of exhaustive enquiries, that neither the Surface Contact system nor the Conduit system will be found to work satisfactorily under the conditions prevailing on the Front-Line at Hastings,” and again they recommended that “the tram lines be laid close to the railings instead of in the centre, as shown on the Parliamentary plans.”

Well, the Company, to get the tram lines laid at any price, have thrown up the sponge and the results of their exhaustive enquiries! And agreed to any system that would take with the majority of the

AMATEUR ENGINEERS

on the Council, ad as most of these care nought for anyone but their little selves, they kill the goose that lays the golden eggs and drive away the best paying class of residents and visitors, by rendering the now splendidly-paved drive – the only drive in the town – objectionable, if not dangerous, to traffic by covering the centre of the road surface with two lines of studs, raised sufficiently above the surface to jolt every carriage that passes over them.

It is good to note that the Aldermen on the Council, men of experience and knowledge of the town’s requirements, voted almost unanimously against the proposal.

There is one system that seems to have been put on one side by the Tramways Company, as well as by the Tramways Committee of the Council and that is the electro car, self-propelled system, which system even now, at the eleventh hour, should be insisted on!

Yours truly,

B. BROMLEY

May 1st 1906.