Island presence detected
US5924652A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Sep 29, 1997 |
| Grant date | Jul 20, 1999 |
| Priority date | — |
| Expiry date | Sep 29, 2017 |
Classification
- Technology area (CPC B)Performing Operations; Transporting
- CPC primaryB61L1/188
- WIPO fieldTransport
- WIPO sectorMechanical engineering
Abstract
A reliable and consistent electrical contact path between the rails of a section of railroad track established by the shunting effect of the wheels and axles of a train is ensured by applying time-spaced, short duration electrical pulses to the rails at a voltage level sufficient to overcome poor wheel/rail contact. Each of the pulses is produced by a generator that discharges a capacitor across the rails. The narrow pulse width inductively isolates the pulse generator and associated track section from adjacent stretches of track, and the spacing between pulses further avoids interference with other types of electrical track equipment. A detector responsive to the voltage on the rails disables the pulse generator when the received voltage exceeds a threshold and thus indicates that no train wheels are present in the track section. In a grade crossing warning system, once activated the pulse generator and detector assume the role of the island detection circuit and maintain the crossing warning.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.