TELPHEKAGE. 



279 



greater, the supports must l)e iieurcr together, mid the cuhles oi' gir- 

 ders heavier. Running parallel to the track rail, either above or at 

 the side, and depending upon the amount of head room, are stretched 

 one or more trolley wires; one wire, if the track be used as a return. 

 If, however, it is desired not to use the track as a return, or to use 

 alternating current, two trolley wires are employed. There are many 

 other details of construction which the illustrations show better than 

 any description. 



Telplwrx. — According to the construction, telphers are divided into 

 three distinct classes, center-hearing, side-bearing, and alternate-bear- 

 ing. The center-bearing has two motors, one on each side of the 

 track; the side-bearing has l)oth motors on the same side, and the 

 alternate has one motor upon one side of the track and the other 

 motoi- upon the other side, l)ut not upon the same shaft. Illustrations 

 of some of these telphers are shown, also the same in operation. All 

 the weight in the side-bearing telpher is utilized for traction, and the 

 load is suspended beneath the driving wheels. Sometimes two telphers 



Pig. 3.— The double telpher; maximum traction; capacity, 4 tons of coal, or 95 cubic feet; speed, 800 

 to 1, 200 feet per minute. Side-dumping bucket operated by telpherman; controlled from either end. 

 Telphers can be operated separately. Three of these double telphers have a capacity of 250 tons 

 of coal per hour over 2.000 feet of track. Labor, power, and maintenance less than 1 cent per ton. 



are connected up together in a single truck, this giving what is called 

 a double telpher; or a trailing wheel is used after a double telpher in 

 order to distribute the weight over a greater portion of the track. 

 This is ne(*essary when the weight of the load to l)e carried is great. 

 Fig. 8 shows quite fully this weight distribution. In all telpherage 

 work gears are rarely used except for very heav,y work or on steep 

 grades. The frames of the later telphers are made in one casting, and 

 the driving wheels are of steel, this having ))een (h^termined to be the 

 best material. 



JIotoTH. — The motors are waterproof and dust proof and are com- 

 pound wound for automatic work. When a telpherman goes with the 

 telpher the series winding is employed. There is also used a special 

 series coil to give greater tonjue when starting. The telpher is placed 

 above the track, thereby keej)ing the motors from injury, while there 

 is also no danger of their coming in contact with the carriers or being- 

 otherwise injured. 



