The first two batches were built by Baldwin Locomotive Works during World War II.

The Big Emmas proved to be the most expensive Berkshires built due to the fact that they were fitted with every refinement known to the steam locomotive builder's craft.

Both designs used 69-inch driving wheels, the same tube diameter, and the same number and size of the flues.

The Nickel Plate Road S-2s and Chesapeake & Ohio K-4s, which called their 2-8-4s "Kanawhas", were also equipped with roller bearings like with the Big Emmas.

However, the Van Sweringen designs all had Baker valve gear, an engine wheelbase of 42 feet, a boiler pressure of 245 psi, a firebox with 90.3 square feet of grate area, and a cylinder stroke of 34-inches.

The Big Emmas, meanwhile, had Walschaerts valve gear, a 42-foot 4-inch engine wheelbase, a boiler pressure of 265-psi, a firebox grate area of 90.2 square feet, 25-by-32-inch cylinders, and 62 tubes inside the boiler.

[4][5] Some of them were eventually converted to canteens to supply extra water for steam locomotives that were used in main line excursion service such as Southern Railway 4501, Norfolk and Western 611 and 1218; Nickel Plate Road 765 and 587; Chesapeake and Ohio 2716 and 614; and Milwaukee Road 261.