Railway control signal interlocking systems
US4270715A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | May 23, 1979 |
| Grant date | Jun 2, 1981 |
| Priority date | — |
| Expiry date | May 23, 1999 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG06F11/181
- WIPO fieldComputer technology
- WIPO sectorElectrical engineering
Abstract
The specification discloses an electronic or computer-based railway control signal interlocking system. Signals representing the settings or conditions of railway control elements e.g. track circuits, signals and points, and their control signals are checked as usual by the interlock equipment to establish route safety. However failures in the system may only be discovered when a change to a control element setting is attempted. Since long periods can elapse between changes a failure may lie dormant for some time. In order to reduce dormant wrong side failure periods to a minimum the signals supplied to the interlocking equipment are periodically switched to a predetermined state chosen to prove that when the interlocking equipment receives the switched signal that a wrong side failure mode does not exist in the switched signal path.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.