John, From what I've read on the net and in articles the BR52 was one of the standard Reichsbahn engines. There were two tender designs a square riveted unit (early?) and a rounded unit that was more easily produced. You could show it pulling most of the available cars - Tank transporter flat cars, and the box cars etc available from ironsides. If they were shipping tanks I would expect it would be many flatcars with similar units. There's a few places to be careful. The original release of the Leopold gun had 1/32nd scale rail trucks - so it would fit with a popular model RR scale. One post indicated that this was later corrected to 1/35th - but that was the only mention of such a change. Basically be careful what you get all has the same track scale. A Morser Karl with support cars may make a interesting set. There's a Yahoo Group that specializes in Military trains. The HO and N scale guys have had many discussions on shipping things like midgit submarines - V-2 Rockets, disassembled Messerschmidts etc.
VLS had some Reichsbahn crew figures - engineer and fireman in a recent flyer.
Hope this helps.
Val Kraut