Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Publication of BE454900ApublicationCriticalpatent/BE454900A/xx
E01B—PERMANENT WAY; PERMANENT-WAY TOOLS; MACHINES FOR MAKING RAILWAYS OF ALL KINDS
E01B9/00—Fastening rails on sleepers, or the like
E01B9/02—Fastening rails, tie-plates, or chairs directly on sleepers or foundations; Means therefor
E01B9/28—Fastening on wooden or concrete sleepers or on masonry with clamp members
H—ELECTRICITY
H04—ELECTRIC COMMUNICATION TECHNIQUE
H04Q—SELECTING
H04Q1/00—Details of selecting apparatus or arrangements
H04Q1/18—Electrical details
H04Q1/30—Signalling arrangements; Manipulation of signalling currents
H04Q1/44—Signalling arrangements; Manipulation of signalling currents using alternate current
H—ELECTRICITY
H04—ELECTRIC COMMUNICATION TECHNIQUE
H04Q—SELECTING
H04Q1/00—Details of selecting apparatus or arrangements
H04Q1/18—Electrical details
H04Q1/30—Signalling arrangements; Manipulation of signalling currents
H04Q1/44—Signalling arrangements; Manipulation of signalling currents using alternate current
H04Q1/444—Signalling arrangements; Manipulation of signalling currents using alternate current with voice-band signalling frequencies
H04Q1/45—Signalling arrangements; Manipulation of signalling currents using alternate current with voice-band signalling frequencies using multi-frequency signalling