I know this is turning the clock back a very long way, but
Railway Modeller for November 1978 carried an excellent article by Rob Ormiston-Chant of LSWR level crossing gates on the New Forest lines. More to the point the article included a scale drawing of the standard LSWR pattern gate, at the odd scale it has to be said of 9/16ths of an inch to the foot (or 11mm to the foot). I've constructed a pair of gates from this drawing to 13mm:1 foot scale, using basswood strip and section, with ironwork cut from sardine tins, track pins to represent coach bolts and bent wire for hinges. A picture of the result, prior to painting, is attached, hopefully, anyway, as I haven't quite grasped the process yet. It was a project that was cheap on materials, but exacting on the eyes.