I had a Marx 1998 switcher missing the Marx shell. I found a Lionel SW2 shell and cut out about 1 inch of it to shorten it to fit the 1998. I painted it black, white and red in the colors of ALCOAs Bauxite and Northern short line railroad from the Bauxite, ARK alumina and chemical plant in Bauxite, ARK to the a major railroads main lines. The Marx 1998 is a great running engine and always beats other engines in racing through the oval and figure 8.
This post is from topic on how I built my layout on OGR forum linked below. This link has details of many kit-bashed and home made cars, buildings, operating accessories including a $10 operating turntable and a round house.
https://ogrforum.ogaugerr.com/...ra-027-layout?page=4
Charlie