The largest trains run on rails 7¼ inches apart. The scale is 1½ inches to the foot for standard gauge or 2½ inches to the foot if you are modeling three foot narrow gauge. It may take two people to pick up a freight car, and some of the engines are truly enormous! Despite these drawbacks this size continues to be the most popular for the live steam enthusiast. The track at Marengo is a mile in length and features a yard, passing sidings, bridges, and operating signals.