Based on the Yellowstone design, the EM-1 was developed by the Baldwin Locomotive Works for hauling coal across the Alleghenies on the Baltimore & Ohio® Pittsburgh Division. A latecomer in steam, the massive, articulated design was the result of wartime restrictions on the construction of more technically advanced diesel locomotives. Between 1944 and 1945, thirty of these behemoths were delivered, lasting in service for just 15 years. During this period they would see operation not only on coal trains, but on mixed freights, mail, and express passenger services (thanks to being fitted with roller bearings). In later years, they could be found west of the Alleghenies hauling lake-bound coal trains, while some of their final duties included fan trips in the late 1950s. Despite at least one being earmarked for preservation, all were scrapped in the early 1960s, bringing the era of big steam on the B&O® to a close. Making its grand return to Bachmann’s HO Scale Spectrum® now with thunderous Soundtraxx® Tsunami2™ DCC and sound, ensuring the legacy of these mighty machines lives on - if only in scale size.