Seeing a lucrative market develop for equipment to drive their fans, in the 1870s they introduced their first steam engines. Over the years, both vertical(up to 150HP) and horizontal(up to 250HP) engines were used to drive fans, blowers and electric generators. Only the 20th century designs had letter model names.
Technological obsolescence ended that product line in the early 1930s. WW2 briefly brought back the vertical engines. The scarcity of skilled Navy mechanics required the use of relatively simple steam engines. The foundry patterns that were still in storage went back into production and hundreds of Sturtevant engines were built for the famous Liberty ships.