What constitutes a module?   A module may consist of one or more boards to make up a section which can be used within a combined arrangement. To make sure there is broad compatability the following standards apply:     Absolutes   Gauge – OO, suggest Peco Code 75 as the maximum code with any variations being 'compatible' at the module joints.   Floor to rail height – suggest 45” as a reasonable figure workable for as many people as possible and inclusive of existing Freemo work.   Hei