You should visit trainsim.com. My son posts there frequently. After many years of playing around with Microsoft Train Simulator, he's now building his own routes from scratch. Downloads real-world topo imagery, converts it into 3-D space using DEMEX, engineers his roadbeds and lays track using track charts, GPS, and other tools to replicate existing or abandoned railroads, or creates fictional routes through new territory. He's been doing scenery upgrades to a couple of commercially-available sim routes that vastly improve the realism over the original product. He puts a tremendous amount of time into the performance factors for rolling stock, track structure, etc. Probably much more complex than what you'd want to do for simple switch move planning. I do believe there's "model railroad" sim software available which modelers use to plan their benchwork and tracklaying beforehand. Might check the sites for Model Railroader and Railroad Model Craftsman magazines.