Communications: electrical – Vehicle detectors
Reexamination Certificate
1999-05-20
2001-11-27
Wu, Daniel J. (Department: 2632)
Communications: electrical
Vehicle detectors
C340S905000, C340S539230, C246S292000
Reexamination Certificate
active
06323785
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The invention relates to an alarm system for use in warning of the imminent approach of a train, and more particularly, to a warning device for cautioning workers of an approaching train, by visual and audio signals.
2. Brief Description of the Prior Art
The typical operation of the Automatic Railroad System includes up to six parallel tracks running around curves, through cuts, fills, bridges, and tunnels maintaining a generally bi-directional train traffic flow. Additionally, there are multiple crossover connections between these tracks so that a train is likely to be on different tracks at different times and locations. Train traffic moves in both directions and at widely varying speeds along these sets of tracks with schedules and timing set and maintained by the control center maintaining the specific area of track. These schedules and timing, however, may be unknown to railroad work crews.
When high-speed trains are involved, approaching traffic must be sensed at distances of approximately one mile in either direction from the work site. At speeds of about 100 miles per hour, the train will close the one mile gap in slightly over half a minute, leaving little warning time. A worker must not only be clear of the train, but must also be out of the range of the suction created by the fast moving train.
Over the years, the warning systems have evolved to keep pace with the increasing speeds of the trains. The traffic warning systems must be portable to be useful wherever the work crew may be positioned as well as operate around whatever type of equipment is present in the work site. The current, prior art approach used with warning systems, has been the hard wiring of the sensor to the alarm, over the one mile distance. It is, however, not unusual for the wire to become broken or frayed at some point over its one mile length, thereby eliminating the effectiveness of the system and endangering the work crew.
The disclosed system provides a wireless system with multiple safety back ups built in. Further, the system provides a reliable system at a cost that does not render the system unfeasible.
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McCormack John L.
Nickell Larry
Van Wilson Marlin
La Anh
Parker Sheldon H.
Wu Daniel J.
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