Forrest W Gagnon
Engineers at Davies Ave So, Littleton, CO

3979091, Sep 7, 1976

Jun 6, 1975

5/584669

Forrest W. Gagnon - Littleton CO
Arthur H. Marsh - Arvada CO

Otis Elevator Company - New York NY

B61L 108

246 8

A communication system for track or guideway operated vehicles is disclosed. The system is adapted for two-way transmission between a vehicle and a wayside station and is provided with a transmission line of special configuration along the wayside. The transmission line comprises three conductors each having a wave configuration with the waves disposed in three-phase relationship and a return conductor which is also of wave configuration. The vehicle transmitter section is provided with an inductive loop which is coupled with the transmission line and is energized with a continuous wave signal. This produces signals on the three phase conductors which have an envelope frequency proportional to vehicle speed and a phase relationship corresponding to the relative position of the wave configurations of the phase conductors. Thus, vehicle speed may be derived by measuring frequency and vehicle position may be derived by counting cycles or pulses from a given starting point. Direction of the vehicle travel can be derived from the phase sequence of the signals in the phase conductors.