THE ELECTRIC RAILROAD.

Marlborough Express, Volume XLII, Issue 10, 13 January 1908, Page 2

THE ELECTRIC RAILROAD.

. BECENT PROGRESS. ■'-.

k (London Daily Telegraph, Nov.-21.) ""V^lt is an age of acceleration. CWnges in modes of transport ; ; sak&, jala&O^ rapidly that we have notiihje to coWder the possibilities of a new system^efore it is ''put into actual practice-Klt seemed; as if, for many .years, theNLondpner -thought only of the horse-drWn omnibus. And then. Almost in a fW hours, he awoke and Tubbed his eyeV at the sight of the various fleets orSanechanically-driv^n , vehicles, which noV ply for hire. It is sometimes arguea^that these new ■methods of locomotion, are not a blessing, but a curse\lt has bee,n jstated that men were ftappier "in the good old days." But_^pring the last century we hare acquireliLa wider of* the world, ajHj. that larger, universe of which it is jhufc a part, than, in all the .sixty Or rV> 3xed centuries preceding it. ':T*Q coming of the calculus, the chemfst'sN test tube, the slide-rule, the ironliorse, and the dynamo has lessoned for many the struggle for-existence and has opened up a realm for +housands who enjoy a fulness of life unknown in other days.- The age of darkness and narrowed bigotry can never return. For if the light of learning should flicker and die out in one land, it will be burning brightly j in another. It is the greatest blassing of the age that knowledge can be so easily communicated. %. discovery made in this country is at once known in America and on the Continent, and a thousand other minds are instantly focussed upon the subject. Together they build up something which we call an " invention." ,JPdr great inventions are never the work of one man, but of many. : .One of the most fascinating problems for the workers in applied science is that of the electrification ■of the railroads. We are now so used to the advantages of electricallyoperated tramcara that perhaps we -do not fully appreciate them. It is estimated that in this country there Are at present 5000 miles of electri-cally-operated track. Over 20,000 motor tramcars are in use. The importance of electricity as a lighting ftgeni has how been eclipsed by its ustj for motive power. Pet . haps the greatest, venture was' the secent conversion to electric traution of the Metropolitan Underground Bailway/ The Londoner is familiar .with his''tube" railways. But of the advantages of electric railways for _susufban work he has had no practical «xperierice. He will not have to wait long. The London, Brighton and South Coast Railway will soon provide him with an object lesson. It i» " the last word " in electric^ traction at this present date; it will influence the design of the equipment ibr other lines. CHECKING THE DRIVERS. Interest has been of late awakened in the question of effecting economies in, the consumption of current by tramcars. Meters have been installed. Not only do they absolutely record the amount of energy consumed by each car, but they form a check on the way in which a, driver handles his car. They also give a record of the condition of the electrical apparatus. It has been noticed that this automatic check 6n the driver has resulted in a saving of from 10 to 20 per cent, of the/energy consumed. Arrangements are/also, made bo that when the car is running dawn hill the electric motor may act as a dynamo and return current to .the line. In this.system thegeare several notches on the controller. Each notch corresponds to a certain definite speedj which varies within quite Marrow limits. , When the handle. ,js placed at a certain notch the car runs at a definite speed, whatever may bo the gradient. . The advantage of running .the electric motors as genorators during a descent is not limited to the economy of current.. .Thßrle is at the driver's command & powerful braking, effect, t attd it will' not lock the wheels. There ,is thus a saving.on brakes and wheels. "LIVE" TRAILS. The ideal system of supplying electricity for' railway wor£ seems to be fey means of .the -utsuUted jthird rail, Which ,'.-ia r "fe4Jr or,',:eteetfrically charged, while tEe- system .iaatf work. Ufce voltage, employe^' is jfrom '50" to 45&P volts—amply .sufficient to c*tt«e death by shock, Bpeclao£ In Vw©t weather. This is the syst<M^(j>f '>Wob•ing for air the lidndon/^in^ergtoVnd and tube t&)i#,syg there are differences" in the method of genorating power.* The advent of the steam turbinß %aa not only revolutionised shipbuilding and design, but it has made a great difference to central station design, The men in the will be glad to know that it »as spelt economy and reduced tariff for electricity* .•:..■■;.• ' It is a much more difficult matter to arrange for a railway train to collect current than is the case with » tramcar. Currents cannot be easily collected by means of the ordinary trolley-wheel at high speeds, owing to the jumping of the wheel at the points of suspension* of the trol-ley-wire. The outcome has been the development of sliding collectors. The simple collector consists of a castiron block, which rests on the rail. !No mechanical pressure, beyond that of ita own weight-—some 301b to 40ib —is exerted. A three-wire system is now being used, two live rails being placed at the side of the track, the running-rails being used as middle wire. A pressure of 100 volts exists ftetween the insulated "REGENERATIVE" CONTROL. Reference has been made to a system of regenerative control on tramcars, but some remarks on what might be called a gravitational regenerative railway, used on the Central London Jlailway, will not be out of place. On the Liverpool overhead system it was found that of the total energy supplied to the rails only 21 per cent, was expended in actual driving, 29 per cent, was spent in the motors, gearing and starting resistances, and f») per cent, on the brakes. TJie question naturally arose as to the method of reducing these losses. One method was seen, and as a result the stations of the Central London Railway were each placed at the top of a little hill; the energy stored in going up the hill helped to brake the train, and was available for restarting. In the driving of the heavy trains on suburban railways the mastor controller, has been introduced. Tlic currents which have to be dsa't with are so large that the ordinary u'amcar controller is quite unsuitable. In J order, therefore, to make all regulating gear compact, the switches are placed beneath the car, and are oper-" ated indirectly v either by pneumatic or magnetic control. The trains are operated on the multiple unit system, every other coach on the train Jbeing a motor coach. In the so-called rheostatic control <of direct current motors there are

considerable losses which are inherent to the system. In alternating current working a great portion of thesevlossesi can he, eliminated. Al-te^nl|]tng''-ct%rent.v Bystlnfc,. a^^kMjf useNi Stbroatf lor mainji«e w's:. sfl&r thsjp\etass 'bfStansporfc jhigK|jsfoHiges ar«ia%olUtelfenecessa;fc andjf pr'lii&h volfsges Wdifh^ad ■lipwjare almost essentiaJiV Tlie th^ee-'p|iaCse. system' pas a number ol advantages which haVe led to its wide adoption. The•• cessity of using a low voltage-is avoided, and the commutator —'the most delicate part of a motor, and one very likely to get out of order when working under the arduous conditions of railway work—is abolished. It also lends itself readily to regenerative braking. The main disadvantage is that two overhead wires are required. There are two,or three different kinds of collectors used in these .wires. -On the Valetellina Electric Railway a specially-designed trok ley wheel is used, but general practice i seems to favour the "bow" collector, in which a spring in the form of a bow presses against the wire. <rhe simplon tunnel electric locomoP%qs are litfced with a modification of%his collector. ThVlatest and most advanced step in the\evcilution of electric traction is the system. It has been largely the outcome of experiments made\ih Milan by, Dr. Tinze in 1903. Sinbe/ that date considerable nctivity has been displayed on the Continent, and in the United States towards developing the singlephase cqnjimutator motor. The first installation in America was commenced in 1904 by the Cincinnati and Indianapolis Traction Company. The current is. supplied directly to the rails from the generator without any intermediate transformation* One of the great advantages of this system is its simplicity, only one overhead wire being needed. At,the same time that it rivals the simplicity of the direct current system over long distances it affords the ity and economy of alternating current transmissions. The total cost of the single-phase alternating current equipment* is less than that of direct current, and the alternating method is more efficient,

In the case of an electrified overhead system the lines hay© to be protected from lightning discharges. Lightning arresters are arranged along the line, the number per mile depending; uponv4he~ exposure of the line. The function of" the arrester'is to convey any discharge to earth through n suitable path, instead of allowing the discharge to pass through the machines. The ideal arrangement for;an electrified locomotive is for it to be perfectly self-contained, carrying not only its motors, but its source of electrical energy. Such a locomotive could be placed on existing steam roads, and no expense would be incurred tyr the erection of overhead conductors, with their necessary j feeders, etc. Secondary batteries each consisting of a sufficient number of cells to supply th& necessary voltage t for lihe motors, and of a size sufficient to supply; the full load current for at least a complete journey, seem necessary for a practical solution of the problem. As there would be rib mains to consider, the battery could be ai low voltage,one, individual cells beinjg Very large i" The difficulty is that such a battery would be exceedingly unwieldy, and a considerable pro])prfciori oj; the energy expended vrouid be1 required'to carry the battery itself. With such a battery of secqiidary. cells .speed regulation coulcl be easily and efficiently ob- | tamed, .and ; ,i regenerative _,braking r would be ' much' simplified." Unfortunately, the tideaL battery for such a purpose remains yet to be produced. We may look for progress in this direction;* Such progress is hiade (ifapidly;;: aometimes it is disappointißgly.slow. ,v . '.