1361, both designated as the official state steam locomotive by the Pennsylvania General Assembly on December 18, 1987.

PRR 3750 was used to haul the Pennsylvania Railroad's mainline passenger trains such as the Broadway Limited.

Despite the attempt by railroad management to replace the K4s with the K5 and T1, the K4s would remain in action until final dieselization in 1957.

PRR historian Dan Cupper gives much credit to a former Chief of Motive Power for the initiative to preserve examples of its most-successful engines at its Northumberland, Pennsylvania, roundhouse.

The Pennsylvania Legislature intervened, and forgave some back taxes in exchange for PC deeding the collection to the state.