Track signalling system
US4074879A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Nov 29, 1976 |
| Grant date | Feb 21, 1978 |
| Priority date | — |
| Expiry date | Nov 29, 1996 |
Classification
- Technology area (CPC B)Performing Operations; Transporting
- CPC primaryB61L23/166
- WIPO fieldTransport
- WIPO sectorMechanical engineering
Abstract
A track circuit signalling system for an electrified rapid transit system using significantly fewer components is provided. Instead of a transmitter and receiver at each track circuit boundary, alternate boundaries have transmitters only; and the intermediate boundaries have two receivers. The coupling units for the two receivers are more economical than the prior art coupling unit for coupling the transmitter-receiver combination. The transmitters on each side of a receiver pair transmit signals on different carrier frequencies. Each transmitter transmits in both directions from its location. Of the two receivers at a given boundary, one is tuned to respond to signals from the transmitter on one side, while the other receiver of the pair is tuned to respond to signals from the transmitter on the other side. For special applications using overlapping track circuits, selected transmitters may be omitted and a single receiver used on each side of the omitted transmitter.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.