CB&Q M-4a Project Part 2: Surgery
The LMB boiler required extensive modifications to make it fit over the Walthers mechanism. The boiler is designed to fit over a motor mounted in the cab. The Walthers motor and weight sits further forward, as typical for more modern mechanisms. I used a Dremel cutting wheel to enlarge the cutout just ahead of the firebox, taking a little off at a time and test fitting the Walthers mechanism until everything fit together without interference. I also removed some of the boiler-mounted details to make access to the area easier. These will be replaced later. Photos show the cylinders of the M-4a are centered on the smokestack, and that’s how I positioned the mechanism along the boiler. This left a space between the rear end of the Walthers frame and the rear endplate under the LMB cab. I used heavy styrene strip to build a frame extension, shaping it to approximate the side bearers of the trailing truck. This assembly also serves as the mounting point for the drawbar. I attached it to the...