Marx brought out its M10000 diesel in the late 1930's , however about that time Marx shifted its attention to steam locomotives and diesels took a very definite secondary role. Marx toy makers felt that steam locomotives with their moving rods, whistle, steam just made for better play things than diesels which had no real moving parts. This continued for a considerable period until about 1950, when it is speculated Marx observed the great success that Lionel was having with the red bonnet Santa Fe and so in that time period Marx set out to create an F-3 selecting the famous Santa Fe livery for their locomotive. They designed and brought out a fully 1/4 " scale, tinplate F-3 which they sold from 1950 to 1974. Interestingly when this locomotive was sold separately (i.e. not in a set) it came with a die cast knuckle adapter that allowed it to pull Lionel cars. So here is the Marx, tinplate, fully lithographed #21 Santa Fe F-3 diesel. This is the only "large" F-3 loco that Marx ever made, they designed a Rock Island loco but it was never produced. They made a number of plastic E-7 locos which were somewhat smaller and not quite to scale.
Best Wishes, Don
