49 CFR 213.321 - Vegetation.
Vegetation on railroad property which is on or immediately adjacent to roadbed shall be controlled so that it does not -
(a) Become a fire hazard to track-carrying structures;
(b) Obstruct visibility of railroad signs and signals:
(1) Along the right of way, and
(2) At highway-rail crossings;
(c) Interfere with railroad employees performing normal trackside duties;
(d) Prevent proper functioning of signal and communication lines; or
(e) Prevent railroad employees from visually inspecting moving equipment from their normal duty stations.