TM 5-628/AFR 91-44
13-3 Clearance requirements, curved track.
a. For each degree of curvature, side
clearances shall be increased 1 (1.50) inches over
that required in table 13-1 and figure 13-1.
b. When an obstruction is located adjacent to
tangent track but the track is curved within 80 feet
of the obstruction, the side clearances shall be
increased by the following amounts: