I’ll second Gary’s comments on Walt’s CD; it has an amazing amount of information about Marx 6" tin and is worth every penny. It basically functions like Walt’s website, and allows the user to look up cars by type or number. If you are interested in 6" tin, you will like the CD!
As I stated before, I like the windups - or Mechanicals in Marx lingo - and 6" tin. I prefer items that are perhaps a bit rough; not only are they economical to buy, but it gives me the feeling that I have someone’s treasured toy that gave them many hours of enjoyment. A plus is that I can run them without any fear of damaging a pristine piece in a mishap. With that in mind, let’s look at a locomotive!
This is a Marx Mechanical #232, the Commodore Vanderbilt:

This green CV is an early pre-war locomotive. Marx was a bit of a late-comer to model trains, taking over Joy Line and beginning production in 1934. Although some reference books list Mechanical CV’s as dating to 1934, the earliest period advertisement for a 232 that I have seen is 1935 (Montgomery Wards 1935 Catalog p. 18-19)… earlier advertisements still advertise Joy Line clockworks. The first Marx trains used the old Joy Line coupler, so the first 232 had what is referred to as a swing-peg coupler that mated with the Joy Line couplers:

The first CV had other distinctive features besides the swing-peg coupler. The governor was located behind one of the front wheels - this was moved to inside the motor in '36. Some have a cover over the bottom of the motor, but this feature was discontinued by the second year, also:

The windup motor featured a small grinding whe