If a dispatcher issues Form D line 11, what are they designating?

Issuing Form D line 11 designates the limits of an area where cab signals are inoperative. This is a critical communication from the dispatcher to the train crew, as it alerts them that normal automatic cab signal information is not functional within the specified limits. This situation requires train crews to operate with heightened awareness, adhering to all signals and speed restrictions manually, since they cannot rely on cab signal technology to provide guidance.

Understanding this designation is essential for ensuring the safety and proper management of train operations in sections of the track where technology may fail or be temporarily unavailable. It essentially sets the safety parameters within which the train must operate, allowing for necessary precautions to be taken during transit through these limits.