The M10 Class is a class of freight locomotives designed by Gustav Othmar at the Eastern & Atlantic's Richmond Works.
In the late '20's, the Eastern & Atlantic's fleet of medium-strength freight locomotives was beginning to show it's age. Mostly consisting of eight-drivered locomotives, the E&A required a new, modern locomotive.
Gustav Othmar had come over from Belgium in the mid '20's, and he decided for the new locomotive to use a ten-drivered locomotive, and picked the 4-10-2 wheel arrangement. The 4-10-2 wheel arrangement had never been used in the East, having only been used in the west on the Southern Pacific and Union Pacific. The M10 Class had three cylinders, like most 4-10-2 classes; one inside and two outside.
These locomotives were powerful, and worked well on the straighter portions of the line. 24 were built at the Richmond Works in 1930-1932, and assigned to freight work between Trenton and Boston. An additional run was built between 1935 and 1936, of 10 more locomotives, and these were assigned to freight work between Philadelphia and Baltimore.