These ten locomotives were built in 1918 by ALCO for the Virginian Railway. Overall width was , so they were delivered without their cabs and the front, low-pressure cylinders and were assembled after arrival. The low-pressure cylinders (on centers) were the largest on any US locomotive; the cylinders had to be inclined a few degrees to provide clearance. The boiler was also the largest diameter of any locomotive; Railway Mech Engnr says "the outside diameter of the largest course is ." but the drawing shows diameter at the rear tube sheet.