International Correspondence Schools · Scranton, Pa. : The Colliery engineer co. · leaf 555
each switch tiecoincide with the middle point of the track gauge placed onthe main track above the tie. 1699. Location of Crotch Frog.—A crotch, or mid-dle, frog is a frog placed at the point where the outer railsof both turnouts of a three-throw switch cross each other.When both turnouts are of… … Fig. 545. main track 6 by a three-throw switch. Let a be the P. C.common to both curves, and b, the location of the crotch ormiddle frog. It is evident that the point of the crotch frog should beexactly midway between the gauge lines of the main trackrails, and if the gauge is 4 feet 8^ inches =…
Railroad engineering
Internet Archive · California Digital Library · Public Domain Mark 1.0. Free to use for anything.
