About 15 years years ago, I began using Barge Cement routinely for one step mounting of running boards- metal, plastic, and wood. A tiny amount does it; the boards almost immediately are tacked-down, the setting time allows manipulation and/or the application of "contact" methods, and…. the boards stay. These are few downsides.  It is right on my mind as I speak inasmuch as I just negotiated with Barge Cement a neat but ornery retrofit of a Kadee running board on a model not designed for it.