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Class Information
Number: 246/128
Name: Railway switches and signals > Electric automatic highway signals, mine doors, and gates > Normally open track circuit
Description: Subject matter where the primary or controlling track-circuit is normally open.
Sub-classes under this class:
Patents under this class:
| Patent Number |
Title Of Patent |
Date Issued |
| 5924652 |
Island presence detected |
Jul. 20, 1999 |
| 5502367 |
Highway crossing control |
Mar. 26, 1996 |
| 5170970 |
Method and apparatus for improving rail shunts |
Dec. 15, 1992 |
| 4672223 |
Proving safe operation |
Jun. 9, 1987 |
| 4365777 |
Train approach detector |
Dec. 28, 1982 |
| 4324376 |
Railroad highway crossing warning system |
Apr. 13, 1982 |
| 4307860 |
Railroad grade crossing constant warning protection system |
Dec. 29, 1981 |
| 4283031 |
System controlling apparatus which compares signals from sensors monitoring passing objects with pre-determined parameter information to control the system |
Aug. 11, 1981 |
| 4283031 |
System controlling apparatus which compares signals from sensors monitoring passing objects with pre-determined parameter information to control the system |
Aug. 11, 1981 |
| 4251041 |
Multiplexing means for motion detectors at grade crossings |
Feb. 17, 1981 |
| 4172576 |
Highway crossing system with motion detecting apparatus |
Oct. 30, 1979 |
| 4151969 |
System for selectively determining the location of a railway car moving along a railway track |
May. 1, 1979 |
| 4120471 |
Highway crossing system with improved ring sustain feature |
Oct. 17, 1978 |
| 4026505 |
Variable high pass coupler |
May. 31, 1977 |
| 3977634 |
Computer for motion sensing device setup |
Aug. 31, 1976 |
| 3958782 |
Shunt enhancement logic circuit |
May. 25, 1976 |
| 3944173 |
Railroad crossing motion sensing system |
Mar. 16, 1976 |
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