ENGINEERING, 





U UK-till conductor. Illld if li-il tii another dynamo 



will set it iii Hint iun in s\ iii|nitliy with the origi- 

 nal. This second dynamo is called, to diMiu- 

 guish it fnuii the original, a " motor." but it is 

 practically identical in construction, and is con- 



Fio. 2. THIS CONDUIT SYSTEM. 



nected by the ordinary mechanical devices with 

 the driving wheels of the car. Precisely why a 

 wheel (dynamo) revolving at one end of a wire 

 should drive another wheel (motor) at the other 

 end, no one has yet found out. It simply does 

 it, and we accept the service half incredulously 

 as yet, but recognizing it as full of promise to 

 the engineer. The connection between the fixed 

 wire and the moving motor is usually effected 

 by means of a grooved wheel fixed upon the end 

 of a slender pole and pressed firmly against the 

 wire by a spring at the foot of the pole. Me- 

 tallic connection is formed through the pole 

 leading down to the motor under the car, 

 whence, after doing its work, it is allowed to re- 

 turn to the power house by way of the rails and 

 a protected auxiliary conductor of copper which 

 takes up the current when the rails fail to act. 

 Such is the trolley system now in use. 



In the conduit system, which bids fair to be 

 the next step in advance in electric railway en- 

 gineering, the fixed wire is carried under ground 

 as in Fig. 2, which represents the Love conduit 



I id 3. PUOPULSION OF HEAVY TRAINS. 



system, now in use on a section of road in Wash- 

 ington. The feeder and the return wire run 

 side by side in a cement conduit about 16 inches 

 deep by 12 inches wide. A "hanger" provided 

 with grooved wheels rests on the wire and forms 

 the connection, precisely as in the case of the 

 overhead trolley. A chie'f difficulty with the con- 

 duit system is the danger from an always possi- 



ble ruh of water too great in volume to be in- 

 stantly carried olF. Slioiilil the water ri-e to the 

 circuit wires the line would forthwith be pura- 

 ly/ed. Then* is small doubt, however, that these 

 liilliculties will eventually be overcome, and the 

 subways at present, u-ed for cable cars may be- 

 come available as electric conduits. 



KILT. 3 shows the probable beginnings of heavy 

 tratlic traction with overhead wires. 



Electric Locomotive. As a pioneer in its 

 class, the electric locomotive sent to the Colum- 

 bian Exhibition by the General Electric Com- 

 pany of Lynn, Mass., was highly interesting. It 

 would perhaps be unsafe to predict that it will 

 ever be to the electric locomotive of the future 

 what the early steam locomotives are to the 

 mighty engines of the present day, for, in pro- 

 portion, far more mechanical science has gone 

 into its construction. It is, however, strictly a 

 pioneer, intended for the comparatively light 

 work of elevated roads and branch lines. Its 

 weight is 30 tons, nominal speed 30 miles an 

 hour, draw-bar pull 12.000 pounds. It is 16-5 

 feet long, 11'5 feet high, 8*33 feet wide, and 

 rests on four 44-inch wheels. The power is fur- 

 nished by 2 motors, acting directly, without 

 gearing, and supported on spiral springs resting 

 upon the truck frames, permitting automatic 

 adjustment to irregularities of the roadbed. The 

 armatures are mounted upon hollow iron cylin- 

 ders surrounding the axles. In a trial "tug of 

 war " with a steam locomotive intended for simi- 

 lar work, electricity was easily vanquished, but 

 the absence of smoke, cinders, and noise, and the 

 presence of general handiness, cleanliness, and 

 adaptability went far to square the account and 

 serve as a foretaste of what may come with the 

 advance of electrical science. 



The Intramural Railway at Chicago suggests 

 possibilities not heretofore realized in regard to 

 rapid transit for large cities. The cars were 47 

 feet long, with transverse seats for 96 passen- 

 gers. The obvious advantage of this arrange- 

 ment is the ease of entrance or exit, even when 

 the car is crowded. At the worst, a passenger 

 has only to crowd past five seatmates. instead 

 of 25 feet of passage and platform packed with 

 standing humanity. Sliding gates were pro- 

 vided at each seat, all controlled by a lever 

 within reach of the motorman, and with the 

 peculiarity of closing only to within about 6 

 inches of one another, so that there was no dan- 

 ger to the limbs of heedless passengers, while 

 the reckless were effectually held in check. In 

 external appearance the motors were hardly to 

 be distinguished from the passenger cars, but 

 each had 4 axles, with a dynamo on each, aggre- 

 gating 532 horse power considerably more than 

 twice as much as the steam engines used on the 

 New York elevated roads. These motors could 

 start their train of 4 cars each and attain a 

 speed of 10 miles within twice the train length. 

 The electric current was supplied by an iron rail 

 laid outside of the track rails, and the current 

 was taken up by a copper shoe. There were 

 many other interesting features in the equip- 

 ment and construction of the road. and the serv- 

 ice that it rendered during the crowded months 

 of the exhibition certifies to its efficiency, not- 

 withstanding it was confessedly designed to make 

 money, not to demonstrate a principle. 





