(under subclass 454) Subject matter having means placed at the crossings of the rails of two intersecting tracks and consisting, in their simplest form, of four solid frogs joined together with rails to form a connected system.
(1) Note. Only structure peculiar to crossings will be found in this subclass and its minor subdivisions. Structures common to frogs and crossings alike will be found in the preceding subclasses.
SEE OR SEARCH THIS CLASS, SUBCLASS:
111+, 273 and 375+, for the structure of the crossing.
SEE OR SEARCH CLASS
238, Railways: Surface Track, 151, for filler-blocks and other devices used as foot-guards in crossings, frogs and mates.
