680 



EAILWAYS, ELECTEIC. 



Locomotive. 



FIG. 3. SEMES TELPHER LINE. 



Carriage 



circuit. A train standing partly on each sec- 

 tion would therefore form a bridge across a 

 simple multiple-arc circuit, precisely as an in- 

 candescent lamp does. This crossing over from 

 one side to the other is done at the supporting 

 posts, at which points the outgoing conductor 

 must he thoroughly insulated. A number of 

 the details of the system have yet to be worked 

 out, and very probably the final forms will not 

 be reached without considerable experiment- 

 ing with actually working lines. The experi- 

 mental line which has been constructed at 

 Weston is arranged on the multiple-arc system. 

 Different forms of rail, square and round steel 

 rods, and wire ropes, are being tried with a 

 view of determining the best form. The line 

 is supported on posts 60 feet apart, and di- 

 vided electrically into sections of 120 feet, 

 the alternate ones of each rail being insulated. 

 The train is of the same length as a section, 

 and consists of seven buckets, each of which 

 weighs one half of a hundred-weight, and 

 can carry a load of two and a half hundred- 

 weight. Tbe locomotive weighs the same as 

 a loaded bucket, so the total weight of a train 

 is a trifle over a gross ton. The motor is 

 connected to the driving-wheels by gearing 

 of a special kind which has very little fric- 

 tion. One pole of the motor is connected by a 

 wire with the leading wheel and the other with 

 the last wheel of the train, the other wheels 

 being insulated from each other, so that the 

 train always forms a bridge from an insulated 

 to an uninsulated section, and the current passes 

 through the motor. Exhaustive tests of the 

 capability of such a road have not yet been 

 made, but Prof. Jenkin says that the experi- 



ence so far gained warrants him in stating that 

 with a line having rails one inch in diameter 

 there can be conveyed a useful load of 1,500 

 pounds on each alternate span of 120 feet, 

 which is equivalent to 16 tons per mile. 

 Moving at five miles an hour, this corresponds 

 to the conveyance of 92-| tons per hour, and, 

 working 20 hours a day, to the transport of 

 1,850 tons a mile a day. The carriages, he says, 

 run as smoothly as bicycles, the grip of the 

 locomotive is entirely satisfactory, and there 

 is no difficulty in insulation even with very 

 high-tension currents. At present it is not 

 proposed to work the lines from one station 

 for a greater distance than five miles each 

 way, so that a station will be required every 

 ten miles. A large number of radiating lines 

 can of course be worked from one station. 



From the above it \A ill be seen that the elec- 

 tric railway is sufficiently advanced to be ready 

 for commercial development. While much, 

 doubtless, remains to be done in working out 

 the details of a thoroughly satisfactory equip- 

 ment, the main features of a successful system 

 have been determined. No new electrical dis- 

 coveries are necessary to the practical reali- 

 zation of this mode of propulsion, and the 

 problems which will be encountered in actual 

 construction are not beyond the skill of the 

 engineer. The essential pieces of apparatus 

 which will have to be used in such a system 

 the steam-engine or water-wheel, the dynamo 

 and electro-motor are all in a commercial 

 shape. The construction of a suitable road- 

 way apparently presents no insurmountable 

 difficulties. From an engineering point of 

 view, therefore, the system is perfectly feasible, 



