Railroad crossing motion sensing system
US3944173A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Apr 17, 1975 |
| Grant date | Mar 16, 1976 |
| Priority date | — |
| Expiry date | Apr 17, 1995 |
Classification
- Technology area (CPC B)Performing Operations; Transporting
- CPC primaryB61L29/286
- WIPO fieldTransport
- WIPO sectorMechanical engineering
Abstract
An apparatus for detecting an approaching train within a track section utilizes a transmitter coupled to the rails at a feed point for applying a current to the track section. There is a receiver coupled to the track section for producing a signal representative of the impedance of the track section. There are devices for utilizing the received signal for detecting train motion, abnormally low impedance and abnormally high impedance of the track section. A normalizer circuit is connected to the receiver for increasing or decreasing the received signal gain within predetermined limits in accordance with variation in impedance of the track section.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.