FROG

A track structure used at the intersection of two running rails to provide support for wheels and passageways for their flanges, thus permitting wheels on either rail to cross the other; 1. An assembly of rails and/or cast steel which carries rail wheels across another rail in a turnout or a crossing. 2. A ramp-shaped steel casting used to roll derailed wheels up to the rail during re-railing operations, called a rerailing frog.