49 CFR §299.433

1. (a)Headlights. Each leading end of a trainset shall be equipped with two or more headlights.
   1. (1)Each headlight shall produce 80,000 candela.
   2. (2)Headlights shall be arranged to illuminate signs in the right-of-way.
   3. (3)Headlights shall be recognized 600 m (1,968 feet) ahead of the cab car by a driver in another trainset or a maintenance person standing in the right-of-way under clear weather conditions.
2. (b)Taillights (marking devices).
   1. (1)The trailing end of the trainset shall be equipped with two red taillights;
   2. (2)Each taillight shall be located at least 1.2 m (3.9 feet) above rail;
   3. (3)Each taillight shall be recognizable 200 m (656 feet) ahead of the cab car by a driver in another trainset or a maintenance person standing in the right-of-way under clear weather conditions;
   4. (4)Taillights of the trailing end of the trainset shall be on when the trainset is in operation;
   5. (5)Taillights shall not be on in the direction of trainset travel, except if the driver shall re-position the trainset in a station. Such re-positioning operations shall be done in accordance with the railroad's operating rules; and
   6. (6)In an emergency situation, the headlight on the rear of the trainset may serve as the taillights in accordance with the railroad's operating rules.