I've been watching a video on "Stationary Steam Engines - Steam Powered Rice Mills in Thailand". These engines are two cylinder, horizontal, expansion engines, with the pistons in-line (single piston rod), and the valve chests driven from a single eccentric and valve rod as well. Would make an interesting model. The video shows a lot of views (although crank is under a cover). I'd like to see and read more of it, if anyone knows of any.