OAR 741-310-0040: Bridges and Tunnels

(1) Except as provided in sections (2) and (3) of this rule, side clearance for bridges and tunnels is 8 feet as measured from centerline of track. (2) Minimum side clearance in tunnels and through bridges may be decreased, above 14 feet 6 inches, to the extent defined by a half-circumference of a circle having a radius of 8 feet with its center at a point 14 feet 6 inches above top of rail directly over the centerline of track. This rule does not alter the 20 feet 9 inches overhead clearance requirement of OAR 741-305-0010. (3) Except where walkways are used by employees engaged in switching, the minimum side clearance does not apply to the lower section of a bridge so long as no part of the structure falls inside an encroachment line drawn from a point 5 feet from centerline of track and level with top of rail, diagonally upward to a point 8 feet from centerline of track at a height 4 feet above top of rail. (4) See Figure 310-3 for a diagram of minimum clearances for tunnels and through bridges. See Figure 310-4 for a diagram of minimum clearances for the lower section of bridges. [ED. NOTE: Figures referenced are available from the agency.]