What must be done when headlight and ditch lights fail at night?

When a train experiences a failure of both the headlight and ditch lights at night, the appropriate response is to continue moving with a white light displayed. This is because the safety of the train and its surroundings must be maintained. The use of a white light serves to provide some visibility to both the train crew and any other trains or personnel that may be in the vicinity, ensuring safer movement despite the failure of the primary lighting systems.

Relying on a white light allows for the continuation of operations, as stopping the train in an uncontrolled manner could pose additional safety risks, such as being struck by another train. The indication of a white light also communicates to others the train's presence and movement, contributing to overall safety on the tracks during the night when visibility is critical.

In contrast, stopping and waiting for assistance could leave the train vulnerable to potential collisions, while proceeding without any traffic being present may not adequately address the immediate safety concerns. Turning back immediately may not be feasible if the situation does not allow for safe retreat. Hence, utilizing a white light while continuing the journey is the best and safest course of action in this scenario.