Granted Patent
Utility
US 5,145,131 · App. 07/676,093
Master-Satellite railway track circuit
Inventor:
Raymond C. Franke
Patented Case
View Patent ↗
Granted: Sep 8, 1992
Filed: Mar 27, 1991
Inventor
Raymond C. Franke
Assignee (at issue)
Union Switch & Signal, Inc.
This patent predates the USPTO's electronic file wrapper — prosecution documents from this era exist only in the Patent Office's paper records. A certified copy of the file history can be ordered from the USPTO's paper archives.