The design was the product of three men; general superintendent of motive power Frank D. Casaneve, chief mechanical engineer Axel S. Vogt, and chief of motive power Theodore N. Ely, Casaneve supervising the overall design, Vogt perfecting the mechanical details and Ely paying more attention to the appearance and external detail.

[5] As the American (4-4-0) type was displaced from top-flight service to secondary duties, tractive effort became more important than top speed.

The rebuilds to D16sb and D16sd gave them a new lease of life in such service, and even by December 1929 there were still 143 examples in operation, mostly in the Eastern and Central Regions.

[2] A pair (1033 and 2082) were sold to the small Kishacoquillas Valley Railroad in Belleville, Pennsylvania and lasted in service until the KVRR's closure in 1940.

Three locomotives were left at the beginning of World War II, numbers 1035, 1223 and 5079; of these, only 1223 retained its slatted passenger pilot.

It operated tourist trains there until 1989, successively leased by the PRR, its successor Penn Central from 1968, and the Railroad Museum of Pennsylvania from 1979.