Railroad grade crossing constant warning protection system
AssigneeAmerican Standard Inc.
InventorJohn J. Kuhn
Life of this patent
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Abstract
A train detection system for protecting a railroad highway crossing having an a.c. transmitter center-feeding voltage signals into the track rails and having a receiver including at least a pair of coils located on opposite sides of the crossing and disposed adjacent the track rails for defining an island zone and for inductively picking up a.c. signals when the island zone is unoccupied and determines the time of arrival of a train at the crossing.
Claims10
A train detector for a railroad highway crossing comprising, a transmitter center feeding a.c. signals to the track rails at the crossing, a remote shunt connected to the track rails on either side of the crossing to establish an approach zone, and a receiver including at least a pair of coils located between the crossing and each of said remote shunts and disposed adjacent the track rails for defining an island zone within said approach zones and for inductively picking up a.c. signals when the island zone is unoccupied.
Dependencies are inferred from the claim text.