The Baltimore & Ohio's class P-7 Pacifics were known as the "Presidents." Delivered by Baldwin Locomotive Works in 1927, they originally bore the names of the first 21 Presidents of the United States (the two Adamses sharing one locomotive). They had 80-inch drivers, 27x28-inch cylinders, and 230 p.s.i. of boiler pressure. Their grate area totaled 90 square feet, and they produced 49,882 pounds of tractive effort. In the late 1930s No. 5304, President Monroe, was streamlined for service on the B&O's Royal Blue between Washington and New York. The bullet-nosed streamlining by famed designer Otto Kuhler became the model for a popular American Flyer toy electric train.

In 1946 the B&O streamlined Nos. 5301-5304 for service on the Cincinnatian between Washington and Cincinnati; the train was shifted to a Detroit-Cincinnati run in 1950. The Cincinnatian streamlining, by B&O employee Olive Dennis, could be considered more tasteful than the more pronounced "bullet" style of the Royal Blue. As rebuilt, No. 5304 was reclassified P-7d; other modifications included an enlargement of the evaporative heating surface to 3845 square feet, with 950 square feet of superheating surface. The locomotive weight was 316,000 pounds. No. 5304 was displayed at the Chicago Railroad Fair in 1948. A. J. Rock captured this locomotive, the former President Monroe and Royal Blue, on the Cincinnatian somewhere in the Detroit area in the early 1950s; his son Tom Rock of Rock on Trains provided the transparency for our collection. The streamlining was later removed and No. 5304's designation reverted to P-7; she was renumbered to 111 in 1957 but was soon dropped from the roster.