The April '05 issue of Railroad Model Craftsman includes a description of a nifty 10-mile granite hauling line in Northern Vermont. This a line you easily model in a train simulator in true scale. You could also base a fictional route on the proposed model railroad layout included with the article, though you might want to stretch it out a bit.
The article, "The Hardwick & Woodbury: A Vermont shortline" by Robert Jones, features history and a number of informative shots of this line that was built in the 1890s and lasted till the mid-1970s. It's prime movers were Shay locomotives. The line connected to the St. Johnsbury & Lake Champlain Railroad at Granite Junction, VT, and included 7% grades and a switchback. Having been built after the excitement of narrow gauge fever, the H&W was standard gauge, but certainly would have been plausible in 3-ft narrow gauge. If modeled in Trainz, the true-scale route would require 20 baseboards. Thanks to Rich Blake, there is already a 3-ft gauge Shay available at Sirgibby’s TrainZONE (http://www.trainzone.co.nz/download.htm). You will also find standard and narrow gauge Heislers and Climax’s at Sirgibby’s. Microsoft Train Simulator users will probably find similar models at the train-sim.com file library.