(1) "Overhead clearance" is that distance measured along a line which is perpendicular to and joins a horizontal plane passing through the top of the highest rail and the lowest point of the overhead structure or obstruction.

(2) "Side clearance" is the shortest distance from centerline of track to a structure or obstruction at the side of the track.

(3) "Track clearance" is the shortest distance between the centerlines of adjacent tracks.

(4) "Height of a freight car" is the distance between the top of rail and the top of running board.

(5) "Width of a freight car" is twice the distance from the centerline of the car to the extreme outside part thereof.

(6) "Icing platforms." The term "Icing Platform" shall include structures used in performing the service of icing, precooling, heating, ventilating and servicing of cars used in the handling of commodities requiring the above services.

(7) "Constituted authority" shall mean the Public Service Commission of the State of Montana.

(8) "Overcrossing" when used in this rule means any point or place where a highway crosses a railroad by passing above the same. Clearances shall be as specified in ARM 38.4.404 and ARM 38.4.406.

(9) "Undercrossing" when used in this rule means any point or place where a highway crosses a railroad by passing under the same. Existing laws pertaining to highways shall prevail.

(10) "Enforcement" shall be by the Public Service Commission of the State of Montana.

(11) "Crossing." An intersection of a railroad and a public crossing in the same place, the means by which one crosses from one side of the railroad to the other.

(12) "Sidetrack or spurtrack." A track which extends a short distance from a main line on branch line, may serve one or more industries.

(13) "Station." A point designated in tariffs and time tables where train(s) may stop for traffic, or to enter or to leave main tracks(s) , or from which fixed signals are operated, and where freight will be received from and delivered to the general public.