TheNational Museum of Science and Technology in Ottawa, Canada is home to three iron horses of the 1930s. The plaques accompanying these beasts states they were the largest of their kind. So large, in fact, these 4-8-4 (4 small wheels up front, eight power train wheels, four small wheels in the back) were so heavy that they couldn’t travel on most routes. Because they saw so little action, they remain in prestine condition. Here are two from Canadian National Railway and Canadian Pacific Railway.