In the pictures below is my own fairly simple conversion of a China dive to a horizontal drive in an AC 6000 for my Union Pacific and BNSF modern 2 rail TMCC
Layout . I started this project years ago , and it laid in a box . When the new Lionel ES44 came out , the side frame for trucks is an exact O scale beauty . The pads for mounting to the original truck blocks match the holes on the Overland bolsters , like they were made for each other . I did have to install 2-56 Heli coils in the side frame holes so a small screw could pass thru the bolster and secure the side frames . I had purchased years ago surplus Overland gear boxes and the bolsters of _bay , I had Andre make 12 bushings to fit the holes in the back side of the side frames and to fit the new axle tips. Bolted together , these roll with a push of the hand. Now onto the stamped metal chassis , it was cut away in the mounting area of the old motors and brass plates shimmed to the correct ride height were the secured to the stamped metal frame , then the trucks attached . A slot has to be cut in the middle of the frame to let the Pittman ball bearing motor (Overland ) and flywheels ride low and line up with the gear towers . All coupler mtg heights , body ride heights are now correct . Stay tuned as I finish this nice loco . A nice feature is the non-metal axle bushings which will eliminate shorting possibility . This has been a slight challenge but all mods were done with a Dremel , and a 2-56 tap and a drill and scavenged parts . This engine is heavy and when you push it by hand all gear boxes turn effortlessly and sit level in a non binding manner.
Although the parts cost roughly $375 , motor and flywheels , side frames , Overland gear boxes and drive shafts and bolsters , plus $175 for a non powered loco. However a similar brass model is way more , So a plastic body model and a brass model power set up makes for a nice project .