Railway signaling systems

Claim 1

A SIGNALING SYSTEM FOR A STRETCH OF RAILWAY TRACK TRAVERSED BY TRAINS EQUIPPED WITH SPEED CONTROL APPARATUS RESPONSIVE ONLY TO A PRESELECTED SIGNALING CURRENT FLOWING IN THE RAILS AND CARRYING AT ANY ONE TIME A SELECTED DISTINCTIVE SIGNAL CHARACTER ESTABLISHING AN ALLOWED SPEED FOR A TRAIN, COMPRISING IN COMBINATION, (A) CIRCUIT MEANS HAVING CONNECTIONS TO THE RAILS FOR SUPPLYING SAID SIGNALING CURRENT HAVING SELECTIONS OF SIGNAL CHARACTER EXTENDING OVER PREDETERMINED SECTIONS OF TRACK, (B) DISTANCE MEANS ALSO WITH CONNECTIONS TO SAID RAILS AND CONTROLLED BY THE PRESENCE OF TRAINS FOR MEASURING INDEPENDENT OF SAID SECTIONS OF TRACK THE RELATIVE DISTANCE BETWEEN A TRAIN WITHIN A PREDETERMINED SECTION OF TRACK AND A LOCATION AT WHICH THAT TRAIN MUST BE PREPARED TO STOP, (C) SELECTION MEANS CONTROLLED BY SAID DISTANCE MEANS AND HAVING CONNECTIONS TO SAID CIRCUIT MEANS FOR VARYING THE SELECTION OF THE DISTINCTIVE SIGNAL CHARACTER CARRIED BY SAID SIGNALING CURRENT IN ACCORDANCE WITH SAID MEASURED RELATIVE DISTANCE.