For the purpose of this part, the following definitions will govern:
(1) “Height” of a freight car is the distance between the top of the rail and the top of the running board;
(2) “Overhead clearance” is the vertical distance between the two (2) rails from the level of the top of the highest rail to a structure or obstruction above on tangent track and from the mean level of the two (2) rails on curved track;
(3) “Side” of a freight car is that part or appurtenance of the car at the maximum distance measured at right angles from the center line of the car;
(4) “Side clearance” is the shortest distance from the center line of track to a structure or obstruction at the side of track up to a distance of fifteen feet (15') and six inches (6") from the top of the rail; and
(5) “Width” of a freight car is twice the distance from the center line to the side of a car as defined in this section.