I've always like the Fairbanks Morse C liner, I guess because I had an HO ABA set that I ran all the time when I was a lot younger.
I have a few of them in O scale and while they aren't state of the art models, they are passable, especially from a distance.
In stock form they don't run that well and putting two power trucks on one unit or even repowering them with mashima motors doesn't help that much.
I've looked at various ways to repower them, and there was even a central locomotive works drive set up for them that has been out of production for years.
I decided to take the drive from an old Weaver Chain drive Alco I had and modify the Rivarossi frame to use it. I finally got the first attempt finished yesterday. It required a lot of modification and styrene fabrication, but it was fairly straightforward.
I was able to use the stock Weaver pick up from the wheels too.
Here are some pictures:
