278 



TELPHEKAGE. 



of hangers. The numbei- of these hang-ers would depend upon the 

 length of the spans. It will be easily seen that it is possiljle to have the 

 center of the spans higher than the ends by merely raising the sus- 

 pension cable and the hanger. This obviates one of the early diffi- 

 culties met in the use of cable for telpherage, as there is now no 

 objectionable deflection in the cable when the telpher approaches a 

 bracket. There are several methods of connecting the track and sus- 

 pension cables by means of the hangers. The sizes of the ca))le, 

 hangers, and brackets vary, depending upon the weight which comes 

 upon each individual span. The support was either simple poles with 

 a bracket, or what is known as the ''A'' construction or ordinary cross 

 bents. Cable construction costs less than solid rail, except where 



aNGLE LINC 



Single linc 





SUSPENStON PRiweiPcE 



Pig. 2. — Other forms of pole consstruction, showing single and double lines. The track cables are 

 supported by another cable, which is called the suspension cable. It would be impossible with 

 long spans to stretch a cable so that under load there would not be con.siderable deflection. This 

 deflection or sag is taken up by the suspension cable. Not only ca!i we make the track cable 

 horizontal but even higher in the center than at the terminals. 



there are many switches, in which cases the })riccs of solid rail and 

 cable appi'oach each other. In general, cable lines arc recommended 

 for straight lines, except where the weight is excessive. 



In solid rail construction, the supports are ordinarily placed 16 

 to 20 feet apai't; longer spans are used if it is not convenient to erect 

 supports. On long spans, the track consists of a girder rail with the 

 track rail above it. It is not possible to give any general rule as to 

 what kind of track it is advisable to use, as this is a factor of the 

 length of the spans and the weight. The weights conveyed thus far 

 })y tcli)h(M-age vary from 125 to LO.OOO pounds, and the cost varies 

 accordingly. It will be readilv understood that when the weights are 



