Page:The New International Encyclopædia 1st ed. v. 06.djvu/886

* ELECTRIC METER. ELECTRIC RAILWAYS. A meter in practice must be accurate to within 2 or 3 per cent, and be so simple in its construc- tion anil operation as to require little care, as it is the usual and commonplace method of ascer- taining' how nuich current is actually consumed bv the patrons of a power station: and its impor- tance is recofjnized and imi)rovements are con- stantly being made in both design and eonstruc- lion. in fact, the increased use of electric lighting has given rise to a form of meter known as the '|)repayment meter.' where the insertion of a coin will so allect the mechanism that the appropriate amount of current is allowed to pass through the mains. For a description of electric meters of all types, the reader can consult Crocker. Electric Lighting, vol. ii. (New York, 1901). ELECTRIC MOTOR. See Dtxamo-Electric Maciiixkrv. ELECTRIC RAILWAYS. Txailways on which the cars or trains are propelled by electric power, either transmitted from central power sta- tions or supplied by accumulators or storage batteries carried on the cars themselves. The first attempt to build an electric railway of which there is any record was made by Thomas Davenport, a blacksmith and wheelwright of lirandon. Vt., in 1835. For a motor he had a revolving electromagnet running between soft iron armatures or pole-pieces, carrying upon the revolving shaft a conuuutator by which the di- rection of the current was regulated. Three years later. Robert Davidson, of Aberdeen, Scot- land, built an electric locomotive for standard gauge railway trucks which made several suc- cessful trips, 'in 1850 Prof. C. I. Page, of Wash- ington, D. C, made a IG horse-power electric loco- motive which was tested on the Baltimore and Ohio Railroad, and developed speed as high as 19 miles per hour. About the same time Moses G. Farmer constructed a small model electric rail- way, which was notable for the fact that a re- duction gear from the motor shaft to the driving a.le was employed, and because the current was supplied to the motor through the rails. All these early attempts at electric propulsion were made previous to the invention of the dynamo, and current had to be obtained from batteries. In these early attempts it was realized that the expense of generating electricity in chemical bat- teries was too great to admit of its application to propulsion on railways. With the develop- ment of the dynamo, and as one improvement and discovery after another was made, the fact was demonstrated that in its use lay the means of transmitting electrical energy for railway operation. It was not until 1879, however, that what may be called the first working electric railway of full size was constructed. This was an exhibition line 1000 feet long, built at the Berlin International Kxposition by Siemens and Halske: the motor was a Siemens dynamo con- nected by double reihietion gearing to the axle of a car capal>le of carrying '20 passengers. In )S80 Thonnis .. Edison and Stephen D. Field, in .meriea, began experimenting, but a contention between them over priority of patents delayed any real results until 188.3. Jleanwhile Siemens and Halske had constructed a third-rail line in Berlin and an overhead-wire line in Charlotten- Inu-g. In 1883 Werner Siemens built a third-rail line six miles long to the (riant's Causewav, in Ireland. Power for operating the dynamo was obtained from a waterfall operating a pair of turbine wheels. In 1883 the Field-Kdison contro- versy was settled by a consolidation of interests, and an exhibition line 1500 feet in length was installed at the Cliicago Railway Kxiiiliilion, upon which was riui au electric locomotive tak- ing current from a third rail, with joint> bonded to improve its conductivity. Later in the same year an overhead line was exhibited in Chicago by C. J. Van Depoele. and aliout the same time Leo Daft built a third-rail line from Saratoga Springs, N. V., to Jlount McGregor. During this time E. H. Bentlev and Walter Knight built a conduit line in Cleveland. Ohio, and later one in Xew York City and one in Boston. The first practical overhead-trolley line was built in Kansas City in 1884, in which double overhead conductors were u.sed with a trolley- wheel riding on top of the wire. In 1885 Mr. Daft constructed a third-rail line at Baltimore and Mr. Van Depoele installed an overlieadtrol- ley line at Toronto, Out. The next steji made in the development of the electric railway in the I'nited States, and the one which diil most to stimulate capitalists and inventors to ihe active interest which has produced marvelous perfec- tion in electric-railway transportation which we witness to-day, was the contract made by the Union Passenger Railway Company, of Rich- mond. Va., with !Mr. 1'. J. Sprague. to equip its 13-mile system of street railways for electric traction. On January 1. 1888. there were 13 electric railways with 48 miles of track in opera- tion in the L'nited States and Canada. There fol- lowed a period of consolidatiini of interests among electric-railway builders, and the modern era of electric-railway development was opened. The history of this growth, so far as it is impor- tant to outline it. can but be given a.s the various modern systems of electric traction arc taken up for consideration. For this purpose the sub- ject maj' be divided into: (1) Overhead-trolley railways; (2) conduit railways: (3) storage- battery systems; (4) electric locomotives and heavy-train systems; (5) central station con- struction and equipment; ((5) oa^rs and motors. Ovebheau-Trolley Railways. The vast ma- jority of electric railways in operation at present are overhead-trollev lines; that is. the current for DUOBAM OP TBOLLEY-CAE CIRCriT. operating the cars is taken from an overhead wire conductor by means of an under-running trolley-wheel carried on a trolley-pole extending upward from the car roof. The current passes down the trolley-pole conductor to ami through the motor, and returns to the central station by way of the raiLs. In a few instances double trol- ley lines have been constructed on which the second conductor provides for the return cur- rent. Trollev-road construction mav be sub-