Hung C Pham

US Patent:

20040201486, Oct 14, 2004

Filed:

Apr 10, 2003

Appl. No.:

10/410844

Inventors:

Thomas Knowles - Norco CA, US
Rakesh Malhotra - Chino Hills CA, US
Hung Pham - Rancho Cucamonga CA, US
John Sharkey - Elgin IL, US

International Classification:

G08B021/00

US Classification:

340/657000, 246/020000, 340/641000

Abstract:

A solid state crossing controller for a railroad crossing signal system with two independent outputs for controlling illumination of lamps in the signal system share a common neutral or return wire, with sensing of a common neutral or return line shared by the two independent outputs to determine any loss of the neutral line. When a failure has been detected in the neutral line, the controller modifies the voltages for the lamps in the signaling system for better illumination of the lamps during the failure condition, such as to the highest voltage available from a battery in the system. Upon detection of the failure in the neutral line, the controller may provide a call or message that there is a failure in the system that is in need of repair. If the failure in the neutral line is intermittent, the controller will resume normal operation after that train, has cleared the crossing. However, a call or message that a failure has occurred in the neutral line is provided. Tests for the failure will be repeated when the next train approaches the crossing. Related methods for determining whether a failure has occurred in the neutral line are also disclosed.