Definitions. In this regulation, the following terms have the meanings indicated: “Main track” means track extending through a yard or between stations, upon which trains are controlled by timetable, block signals, interlocking rules, interlocking signals, or special instructions. “Overhead clearance” means the vertical distance from the top of the highest rail to a structure or obstruction above. “Side clearance” means the shortest horizontal distance from the centerline of track to a structure or obstruction at the side of the track. Exemptions. Provided reasonable safety is maintained, this regulation may not be construed to prevent: Movement or distribution over tracks of material necessary to construct or maintain the tracks; or Movement of work equipment used to construct or maintain the railroad. Overhead Clearance. Except as otherwise provided in this regulation, the minimum overhead clearance above tracks used to transport freight cars shall be 22 feet. The clearance required by §C(1) of this regulation does not apply to: Engine houses and locomotive service facilities; Tipples; Facilities used to load or unload bulk commodities; or Electric wires and equipment necessary to operate trains by electric energy, if railroad employees are prohibited from being on the tops of moving closed cars where the required clearance is not provided. Existing Structures. Structures constructed before July 28, 1953 may be maintained at existing clearances, except that, whenever the structure is relocated or reconstructed, the clearance required by §C(1) of this regulation shall be provided. Existing tracks may be reconstructed under the existing structure at existing clearances. Additional tracks may be constructed under the existing structure at the same clearances as existing tracks. Overhead clearance at the entrance to and within a building may be less than 22 feet but not less than 18 feet if all cars, locomotives, and other equipment are required to stop before entering the building. Side Clearances. Except as otherwise provided in this regulation, the minimum side clearance from the centerline of tangent railroad tracks used to transport freight cars, to structures and obstructions above the top of the rail, shall be 8 feet 6 inches. The clearance required by §D(1) of this regulation does not apply to: Engine houses and locomotive service facilities; Tipples; Facilities used to load or unload bulk commodities; or Inter-track fences on the centerline between tracks. Structures, including platforms and tracks, constructed before July 28, 1953, may be maintained and extended at existing clearances, except that, whenever the structure is relocated or reconstructed, the clearance required by §D(1) of this regulation shall be provided. Structures adjacent to curved tracks shall have additional side clearance to compensate for the track curvature, super-elevation, and car design. Platforms. Platforms constructed before July 28, 1953 with side clearances less than that required by this regulation may be extended at the existing clearances, provided the extension is not in connection with the reconstruction of the platform. Platforms, except platforms 4 feet or less above the top of the rail and adjacent to main or passing tracks, may have clearances less than 8 feet 6 inches from the centerline of track on one side of the tracks only, if: A clearance of 8 feet 6 inches is maintained on the opposite side of the track; or The distance from track center to adjacent track is at least 13 feet 6 inches. Passenger platforms more than 8 inches but not more than 4 feet above the top of the rail shall be at least 5 feet 7 inches from the centerline of track. Passenger platforms 8 inches or less above the top of the rail shall be at least 5 feet 1 inch from the centerline of track. At entrances to and inside of warehouses and industrial buildings, side clearances, other than for platforms, shall be at least 8 feet from the centerline of track. Switchboxes, switch-operating mechanisms, and accessories necessary to control and operate signals and interlockers, which project 4 inches or less above the top of the rail, shall be at least 3 feet from the centerline of track. When it is not practicable to provide clearances otherwise required by this regulation, the center spindle of signal and switch stands 3 feet or less above the top of the rail, located between tracks, shall be at least 6 feet from the center line of track. Through bridges, tunnels, water columns, and oil columns shall be at least 8 feet from the centerline of track. Clearances for through bridges, clearances for water barrel platforms and refuge platforms on bridges and trestles not provided with walkways, and clearances for handrails, water barrels, water columns, oil columns, block signals, and stock chutes, when all or portions of them are 4 feet or less above the top of the rail, may be decreased to the extent defined by a line extending diagonally upward from a point level with the top of the rail and 5 feet distant laterally from the centerline of track to a point 4 feet above the top of the rail and 8 feet distant laterally from the centerline of track. The minimum clearance for handrails and water barrels on bridges with walkways shall be 7 feet 9 inches. The lesser clearances for handrails and water barrels authorized in §D(10) of this regulation do not apply to through bridges if the work of trainmen or yardmen requires them to be on the deck of the bridge to couple and uncouple cars on a switching lead. Overhead and Side Clearance—Exceptions. The overhead and side clearances required by this regulation may be decreased to the extent defined by a straight line extending diagonally downward from a point 4 feet from the centerline of track at 22 feet above the top of the rail, to a point 8 feet 6 inches from the centerline of track at 15 feet 3 inches above the top of the rail. For tracks located at the entrance to and within a building, overhead and side clearances may be decreased to the extent defined by a straight line extending diagonally downward from a point 4 feet from the centerline of track at 18 feet above the top of the rail, to a point 8 feet from the centerline of track at 14 feet above the top of the rail. Canopies at one side of the track at freight platforms may be constructed 4 feet or more from the centerline of track, if: The height of the canopy is at least 17 feet 6 inches above the top of the rail; and Either of the following apply: Clearance of 8 feet 6 inches is maintained on the opposite side of the track from the canopy; or The distance from track center to adjacent track is not less than 13 feet 6 inches. Clearance Between Parallel Tracks. Except as otherwise provided in this regulation, the minimum distance between the centerlines of parallel track shall be as follows: Two parallel main tracks --- 4 feet; Yard and side tracks --- 13 feet, 6 inches; Track other than main or passing track, which is parallel to main or passing track --- 15 feet; Where passing track is at least 15 feet from main track, other track adjacent to passing track --- 13 feet, 6 inches; Two parallel ladder tracks --- 19 feet; Ladder track parallel to other track --- 18 feet; Team, house, and industry track --- 13 feet; Tracks constructed before July 28, 1953 may be extended without increasing distances between tracks. Other Conditions and Obstructions Adjacent to Tracks. Merchandise, material, or other articles may not be permitted to remain adjacent to any track at a distance less than 8 feet 6 inches from the centerline of track. A line or other marker shall be maintained at a distance of 8 feet 6 inches from the centerline of track, on all platforms except passenger platforms, to indicate the space which shall be kept clear. The space between tracks ordinarily used as a walkway by train and yardmen and other employees in the discharge of their duties, and the space beside those tracks within 8 feet 6 inches of the centerline of track, shall be kept in a reasonably suitable condition for that purpose. Compliance. Except as provided in this regulation, a railroad company may not operate or permit to be operated any car, train, locomotive, or other equipment over its own tracks, or industrial tracks directly or indirectly connected with its own tracks, if: Overhead or side clearances or clearances between tracks are less than the minimum prescribed in this regulation; and After July 28, 1953, tracks or structures adjacent to tracks are constructed or reconstructed by: The railroad company; or Others, if the railroad company has the right to control the construction or reconstruction.