RAILWAYS, ELECTRIC. 



which it is entering and turned off from the 

 one which it is leaving. The train thus always 

 puts between itself and a following train" a 

 complete section, which can not be supplied 

 with current until the forward train has en- 

 tered the next section. Any following train 

 entering this^blocked section is quickly pulled 

 up, both because it is deprived of current, and 

 because it is powerfully braked by the electro- 

 motor, whicli by the conditions of the block 

 becomes at once a generator on a short circuit. 

 In leaving this section the preceding train not 

 only cuts off the supply of electricity to it in 

 such a way that it can not be turned on again 

 by any following train until the first is in the 

 second section ahead, but it connects the two 

 rails electrically together. There is therefore 

 a complete metallic circuit, of practically no 

 resistance, established between the terminals 

 of the electro-motor of the following train 

 when it runs on the blocked section. The 

 motor, being in motion from the supply of 

 current in the preceding section, is thus in- 

 stantly converted into a dynamo working on a 

 short circuit, and the current generated by it 

 brings it to a stop. The great merit of this 

 system of blocking is, that it depends upon the 

 essential conditions of the working of the line, 

 and not upon special mechanism, which may 

 get out of order. So long as the line is in 

 working order the sections will be successively 

 blocked by the movement of a train, but when 

 it is not in order trains can not move, and hence 

 all danger of collision between following trains 

 is absolutely prevented. Ayrton and Perry 

 have also perfected, for use with their system, 

 a motor which is automatically governed, so 

 that the speed is constant whatever the load. 



Telpherage. The facility with which electric 

 power can be divided and applied at any de- 

 sired point, and the possibility it gives of con- 

 trolling a line of moving vehicles from the 

 point at which the current is generated instead 

 of from the train, has led Prof. Fleeming Jen- 

 kin to design a system of aerial transportation 

 to which he has given the name telpherage. 

 The road consists of a light conducting rail, 

 which may be a round steel rod, or a wire 

 rope, strung along on poles at a sufficient dis- 

 tance above the ground to clear obstacles. 

 The vehicles for this form of railway consist of 

 suspended buckets, or u skips " as they are 

 called, connected together by wooden strips. 



A number of such vehicles, provided with an 

 electro motor in a separate frame at the head 

 of the string of carriages, constitute a train. 

 As the load is distributed over a considerable 

 distance, the supporting rail or cable can be 

 light, and the whole structure may be com- 

 paratively inexpensive. There is no need of 

 grading or of bridges, the line being strung 

 across country with the same facility as an 

 ordinary telegraph line, and with no more in- 

 terference with the ordinary use of the ground. 

 Prof. Jenkin has designed the road primarily 

 for the transportation of freight, but it seems 



possible to adapt it to passenger service. He 

 does not regard it as a substitute for the ordi- 

 nary surface road, but as affording a means for 

 the cheap transportation of freight through 

 districts in which the traffic would not be suf- 

 ficient to warrant the building of the more 

 costly surface line. In conjunction with Pro- 

 fessors Ayrton and Perry the system has been 

 worked out in a practical form, and an experi- 

 mental line has been built at Weston, England. 

 The self-governing motors of these latter in- 

 ventors as well as their automatic block system 

 have been adopted. These motors are espe- 

 cially* applicable to such a line, as they are of 

 small weight in proportion to the power devel- 

 oped, a motor weighing only 96 pounds being 

 capable of giving one and a half horse-power. 



The cables are attached to the supporting 

 posts, so as not to interfere with the passage of 

 the trains, by means of saddles placed at the ex- 

 tremities of cross-arms. These saddle* are 

 curved in a vertical plane so as to avoid an 

 abrupt change of direction or corners in the 

 cable roadway. 



Two modes of constructing such lines have 

 been devised, depending upon the way in which 

 the current is applied, which the inventors 

 term the " series " and " cross-over parallel " 

 systems. In the former the line is divided into 

 a number of successive sections, the electric 

 connection between which can be broken by a 

 passing train, and restored again automatically 

 as the train moves on. The trains must be 

 slightly longer than a section, so as to avoid the 

 possibility of their running on to a section and 

 being deprived of power. With this construc- 

 tion, when a train is partly on one and partly 

 on the succeeding section, the direct connec- 

 tion between the sections is broken, and the 

 current has therefore to pass through the 

 electro-motor. As the train moves on, it opens 

 the connection between the section it is on and 

 that immediately ahead, and closes the con- 

 nection with the section just left. In this way 

 the motor of the train is always supplied with 

 current by the use of a single conductor. All 

 the trains on the line are thus arranged on the 

 line like a string of arc-lamps, the current go- 

 ing through the motor of each train in succes- 

 sion. One half of the length of the line con- 

 stitutes the "up" and the other half the 

 " down " line. The engraving, Fig. 3, shows 

 this form of line, from which it will be seen 

 that it is a very simple affair. In the other 

 form, the " cross-over parallel," two conduct- 

 ors are used, but as one of them maybe the up 

 and the other the down line there is no disad- 

 vantage in the arrangement. The two con- 

 ductors are arranged so that there are two cir- 

 cuits, one the outgoing, the other the return, 

 only the first of which needs to be insulated. 



These circuits are not, however, disposed so 

 that each rail forms one circuit, but each of the 

 two circuits crosses from one .rail to the other, 

 so that alternate sections of a rail are portions, 

 the one of the outgoing, the other of the return 



