California Code, Public Utilities Code - PUC § 7607

Every railroad corporation, or receiver or lessee thereof, operating any line of railroad in this State, shall equip all locomotive engines used in the transportation of trains over the railroad with electric or other headlights which will project sufficient light to enable the locomotive engineer to observe clearly a dark object the size of an average man, at a distance of not less than 800 feet on a dark, clear night while his train is running at a rate of speed not less than 30 miles per hour.

This section shall not apply to locomotive engines regularly used in the switching of cars or trains or used exclusively between sun up and sun down, or going to or from repair shops when ordered in for repairs, nor to locomotive engines used on short lines or local lines where in the judgment of the commission, the headlight required by this section is not necessary for the preservation of public safety.

Any railroad company, or receiver or lessee thereof, who violates this section, is liable to the State for a penalty of not less than one hundred dollars ($100), nor more than one thousand dollars ($1,000), for each offense.  Suit shall be brought to recover the penalty in a court of competent jurisdiction, in the name of the people of the State of California, by the Attorney General or by the district attorney of any county in or through which the railroad is operated.