574 POPULAR SCIJ^JNCE MONTHLY. 



shoes can be caught. Thus, unless the slot can be dispensed with 

 the greater beauty overhead is obtained at the expense of increased 

 danger on the street surface. There are quite a number of under- 

 ground conductor systems in which the slot is not used, the current 

 being conveyed to the car by contact made with plates set at suit- 

 able intervals between or along the sides of the tracks, and on a 

 level with the street surface. Many of these arrangements appear 

 to be quite practical, but none of them can attract the attention 

 of railroad managers unless it can be constructed at a reasonable 

 cost. 



About two years ago the New York, New Haven, and Hartford 

 Railroad published a report of the performance of a branch line 

 that was equipped with electric motors, the current being conveyed 

 to them by means of a third rail. Some of the sensational dailies 

 at once took the matter up and heralded the third rail to the public 

 as something entirely new and sure to supersede the trolley. Now, 

 as a matter of fact, the third rail is one of the oldest 



f" arrangements that have been used, and Avas in daily opera- 

 tion in Baltimore in 1886. It is a very cheap system and 



well adapted to roads owning 

 the right of way or running 

 upon elevated tracks, but could 

 not be used on public high- 



FiG. 31.— Cross-section of Railway Track, WayS Or Streets. The third-rail 

 SHOWING A Modification of the Thihi.- gygtem in itS simplest form is 

 RAIL System. "! . -n. i • i 



shown m Fig. 29, which repre- 

 sents a section through the roadbed. The log A represents a tie 

 or sleeper, and c c are the track rails, while h is the third rail 

 through which the current passes to the motors. "Between the rail 

 h and the tie A is placed a piece of insulating material, a, of such 

 dimensions as may be necessary. If the track is high above the 

 surrounding ground, so as to not be submerged when there is a 

 heavy fall of rain, a may be thin, but otherwise it must be of suffi- 

 cient thickness to raise the rail above the high-water mark. The 

 car is provided with a wheel or brush to bear upon the rail h. 



This is the construction used upon the New York, New Haven, 

 and Hartford Railroad, as can be seen from Fig. 30, which is a 

 photograph of a section of the road. The third rail, it will be 

 seen, is raised but slightly from the ties, just about as sho^vn in 

 Fig. 29. One objection to this construction is that persons and 

 animals can receive shocks by touching the center rail and one of 

 the side ones at the same time, as, for example, by standing with 

 one foot on each. Such shocks would not prove fatal to men, as 

 the currents used for railway work are not of a sufficiently liigh 



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