Geographic relay system for railroad interlocked routing

In this system, whose original purpose was to build the control circuits from standard building units, the connections are made in the same order as the parts represented by the relays follow in the track. The advantages claimed are: easy planning of the system and cheaper production, simple installation, testing, repair and modification (if desired). With simple additions it is possible to obtain the route setting, flank protection and signal aspect selection. Connections and working of the scheme are explained on partial diagrams. Particulars of installation of relays in racks and their connection by means of "geographic" cables are given.