Perpetually seeking more powerful and efficient locomotives, the Pennsylvania Railroad introduced the K4s Pacific as its new standard passenger power in 1914, blending the best attributes of successful locomotives such as the E6 Atlantic and earlier Pacific types. Powerful and fast, the K4s quickly became the standard power for passenger trains across every division and schedule on the railroad, from local service to mail, express, and the "Blue Ribbon" fleet, and it remained so successful that it outlasted most other Pennsy steam classes and worked alongside newer diesel-electric power until the last days of steam. Built by the Pennsylvania Railroad at Juniata, Pennsylvania, in March 1920, No. 3750 spent most of its service life hauling commuters on lines east of Harrisburg, though one early highlight was pulling President Warren G. Harding's funeral train out of Washington, D.C., in 1923. After its last revenue run in October 1957, No. 3750 awaited scrapping in the West Philadelphia roundhouse, but in 1958 it was chosen for preservation after the first K4s, No. 1737, had deteriorated too badly to be saved. No. 3750 was then stripped of its identity and given No. 1737's number plate, remaining disguised in the Pennsylvania Railroad's historic collection at Northumberland, Pennsylvania, until its move to the Railroad Museum in Strasburg, Pennsylvania, in 1969, where it was restored to its true identity. In 1987, Governor Robert Casey signed House Bill 1211 making the Pennsylvania Railroad's K4s the official state steam locomotive of the Commonwealth of Pennsylvania.