Pere Marquette 4-8-4 from 1941

From Trains magazine--

"Not only is it one of the most active mainline steam locomotives of the past 25 years it is also an iconic symbol of steam’s greatest technological leap forward: the development of Super Power technology, introduced in the 1920s by Lima Locomotive Works of Lima, Ohio. Built in November 1941, Pere Marquette 2-8-4 No. 1225 is now the pride and joy of the Steam Railroading Institute, based in Owosso, Mich. Every time it runs, it exhibits the traits that helped the Super Power concept transform the closing decades of steam.

"The 1225 was one of 39 Berkshire-type locomotives fielded by Michigan’s Pere Marquette Railway, a relatively small but heavy-duty railroad serving the state’s vast industrial scene. The PM was owned by the Van Sweringen interests of Cleveland, which also owned the Nickel Plate Road, Erie Railroad, and Chesapeake & Ohio, among others. Together, the Van Sweringen roads developed several specific locomotive designs under the supervision of the company’s Advisory Mechanical Committee. All AMC engines featured the main feature of Super Power: a large firebox supported by a four-wheel trailing truck, capable of generating the volume of steam required for high-speed, high-horsepower operation."

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