How does one know which trackside signs (not signals) to use (for what purposes) and where they would go on a layout when many prototype signs consist only of a letter, a number or a symbol of one kind or another and no wording? My GN freight layout, c. 1945-1955, is a small 5' x 7' with a double reverse loop, five track crossings by road, a wayside siding and two freight depot sidings, so there would be a need for only a modicum of signage. I've already placed crossbucks where the roads cross the tracks. What other non-operational signs would be appropriate and practical for the GN line in my era? Color photos with interpretations (uses) and appropriate locations along the route would be most helpful. I've already contacted the GNRHS, but did not receive a helpful reply. I've also since learned that the only books even remotely related to my question are long-winded recitations of rules and regulations, with basically zero graphics, that were written for railroad employees, not the general public.