Use of Railroad Tracks for Carrier Telephony and as Long-Wire Antennas for Transmission of Long-Wave Radio Signals

Investigations were made of the performance characteristics of manmade structures (i.e., railroad tracks, buried pipes, and sewer lines) for VLF signal transmission. Electromagnetic coupling devices designed for signal transmission are discussed. Signal transmissions over a distance of up to 15 miles were achieved with a consumption of less than 10 watts (nominal 48 kHz) transmitted power. A single ferrite loop was used as a receiver. Impulses picked up along fences and other metal structures denote signal re-radiation by railroad track. Results of these experiments indicate that railroad tracks act as signal ducts, and possibly, long-wave antennas.