| 摘要 |
<p>(Case No. 7022) 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 inland 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.</p> |
