Use this form to report a condition that hinders your view of signals or
crossings due to vegetation.

The following is from the CFR Part 49

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.