Except in foggy or stormy weather, or when closely approaching or passing over public crossings at grade, or when other conditions make it inadvisable, headlight must be dimmed under conditions outlined below:
In yards where engines are employed and at stations where switching is being done;
When closely moving behind or when standing behind another train;
On double or three tracks when approaching train in the opposite direction;
In CTC territory, when meeting train and it is not necessary to stop for opposing train;
While standing on main track awaiting arrival of an approaching train that is to take siding, but not until approaching train dims its headlight as a signal for the standing train to do likewise;
When passing engine or rear of train, to afford identification of moving train;
Approaching stations where train orders or messages are to be handed up by operator;
At other times to permit passing of signals or when the safety of employees or others requires.