Thanks very much Mark and Jeremy for your comments!
Mark ... the diorama will have several wagens ... this will be pulled by Trumpeters BR52 and then another wagen, behind it loaded with a panther. See here .
Jeremy ... Ommr and Ssys were abbreviations to describe the class of German railcar ... much like the US used CCKW, DUKW, etc. Both the Ommr here and the Ssys for the panther are plastic kits made by Dragon.