I am a State licensed pesticide applicator. It is my experience that FAR more environmental damage is done by an uneducated public applying chemicals, improper storage/disposal, or outright dumping of old stuff just to get rid of it, than any responsible, trained, licensed applicators
doing what they do as professionals.
I doubt the State of Alaska is going to turn a blind eye to any railroad spraying chemicals all willy-nilly along their ROW, and will insist it be done by certified applicators.
Of course, "better" is a subjective term, and I am sure the RR would happily tender anyone's offer to clear their ROW on a volunteer basis, understanding that such volunteer/s be safety trained, certified, and probably bonded and insured.
Better living through chemistry !