I'm after information on the color of ballast used on the mainline and spurs of the Great Northern in the 1950s. My layout will have pine forest scenery of Montana or Washington. I'm going for a small mainline passthrough shelf layout where engines can refuel and sand and continue on witha few local industries. I'd also like to know the types of signes used, whistle, slowplow flange lift etcadn the type of signals used. http://www.trainboard.com/grapevine/showthread.php?146599-Small-N-Scale-Shelf-Layout-How-is-it Thank you in advance for your help.