NTSB issues safety alert regarding LED and incandescent signal visibility

Written by Jenifer Nunez, assistant editor

The National Transportation Safety Board (NTSB) issued a Safety Alert that focuses on the visibility of railroad signals.

 

According to NTSB, light-emitting diode (LED) railroad signals may mask nearby incandescent signals, preventing incandescent signals from being visible to train crews. If LED and incandescent signals are installed in close proximity to one another, the LED signal may appear brighter or closer, causing crews to confuse the sequence of the signals as they approach. This effect may be more pronounced the closer the train gets to the signals.

This alert highlights actions to avoid accidents by identifying locations where the close spacing of signals may cause a signal to either mask or visually dominate another signal, especially at locations where LED and incandescent light units have been installed in close proximity. These actions include evaluating the railroad computer-aided dispatching software to prevent confusion when lining routes non-sequentially at multiple control points; conducting a hazard analysis that includes testing signal visibility with input from train crews and through the use of configuration management.

 

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