Nice photos Steve and you are right, they did not get the attention that that bigger sisters did. They had an unusual throttle that worked in a U-shaped pattern...to go from forward to reverse, you had to shove the thing all the way forward, then either move it up or down, I can't remember which, and then come back toward you using another gate.
Al Shelton told me a humorous story concerning these when they were new. I guess the brake stand was not located all that well and most hoggers had to duck back inside the cab to reach the independent handle. This was not good when trying to watch for signals, so a number of enterprising enginemen stuck a long piece of hard bubber hose over the brass handle and used it as an extension. This was taboo with the company and you didn't dare get caught with it on while you were aboard the engine. Well this one guy gets off shift and was heading home when he remembered that he left the hose on and called up and got ahold of the next shifts engineer on that F-M. When he told him about the rubber extension, the other guy told him he didn't like using them because the extra length gave too much more pressure to the brakeshoes and made the engine wheels slide! 45 lbs. on the brake cylinders is 45 lbs., it made no difference at all.