I've never been much of a train nerd, aside from the usual curiosity watching them pass whenever you get stuck at a crossing. I did have a train set as a kid, but I have no idea what happened to it. And folks right here in Colorado will be in for a treat before July is finished, as Big Boy No. 4014 - the world's largest steam locomotive still in operation today - will make a pass through the state of Colorado on July 27, 28 and 29. You can track Big Boy and see it's schedule across the United States by visiting the Union Pacific website.