While narrow gauge equipment is not subject to the full requirements of 49 code of federal regulations part 231, there are statutes that cover some grab irons and some sill steps. 231.1 contains the regulation for standard gauge cars for boot guards
49 CFR 231.1(e)(4)(i)
(4) Manner of application.
(i) Metal ladders without stiles near corners of cars shall have foot guards or upward projections not less than 2 inches in height near inside end of bottom treads.
(ii) Stiles of ladders, projecting 2 or more inches from face of car, will serve as foot guards.
Regards
Steve