Railway switches and signals – Block-signal systems – Automatic
Patent
1975-04-16
1976-10-26
Blix, Trygve M.
Railway switches and signals
Block-signal systems
Automatic
246125, B61L 2106
Patent
active
039879895
ABSTRACT:
A railway signal system detects a train approaching the system tie points to a railroad track by transmitting in the track a modulated AC carrier wave signal, which is attenuated by the variable shunt effect of an approaching train, and monitoring the track signal in a receiver that responds to signal variations caused by such an approaching train to drop a signal relay, which operates a gate, flasher, or the like at a grade crossing. The track signal is normally automatically regulated to be within a voltage window, and a continuous system latch up feature precludes pick up of the signal relay upon occurrence of a broken rail or high track signal, for example, caused by a very high impedance ballast, until manually reset. A time delay circuit delays pick up of the signal relay after motion has been first detected, and a bypass circuit for a low track signal detector allows system operation even after an unexpected shunt occurs on a monitored section of track. Moreover, an automatic gain control in the receiver reduces ring-by time to a minimum when a train leaves the system tie points, which define a monitored track island.
REFERENCES:
patent: 2975272 (1961-03-01), Renick
patent: 3696243 (1972-10-01), Risely
patent: 3777139 (1973-12-01), Peel
Blix Trygve M.
Chase D. A. N.
Eisenzopf Reinhard J.
Erico Rail Products Company
LandOfFree
Railway signal system does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Railway signal system, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Railway signal system will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-181097