Vitrified clay third rail insulator for Chicago elevated railway

VITRIFIED CLAY RAIL INSULATORS.

Realizing that the wood blocks used for insulating its third rail must in course of time give way to the ravages of the weather, the Metropolitan Elevated Railroad, of this city, is experimenting with various forms of insulators to displace the wooden blocks when the time comes that the latter are no longer serviceable. The accompanying engraving shows one of the most promising forms. It is the design of P. Haley, a contractor who has done some work for the road. The insulating material is a large block of vitrified clay of the form indicated by the engravings and coated with a very hard smooth glaze, which is good to resist moisture. The material seems to be immensely strong and insulation tests of it show it to have as high an insulation resistance as porcelain. To make the iron supporting pin tit the insulator tightly, melted lead is poured around it. There seems to be no good reason why—if vitrified brick will serve as a paving block—this Imitator should not have ample mechanical strength and the fact that it has a high insulation resistance makes the outlook for its success very promising.