This is not an aviation subject, I know, but if once in a while I see guys showing automobiles on this forum, this might be allowed.
I do like armoured trains. I have for many years.
These days there are numerous kits available for both armoured trains and railroad guns.
There many available in G scale or G gauge. They come from the static model companies. like Trumpeter.
However, not only are they non-running but they are 1/35 scale, which is a bit smaller than 1/32 or #1 scale..In any event you will have to figure out how to make or modify trucks so it will run on G gauge tracks
Combat Models (combatmodels.us/) has the U.S. Naval 14" railroad gun that were used in W.W.1 to good effect. It is a vacuform model in 1/32 scale. It is not listed but he has the parts and can whip up a kit for you upon request.
I buy most of my military RR kits in 1/35 off of eBay. Search for Armored trains, railroad guns,
You will find a number in HO gauge and more in roughly OO gauge. Since I limit my RR modeling to a minimum of 1/35 scale and go up from there these smaller trains do not interest me; but some of you may like them.
On the other hand, There are kits in 1/25 scale. But these are paper card models. This is really a form of scratch building for if you want a more permanent model you can use these kits simply as patterns. You can then cut the parts out of wood, metal or plastic sheet. But they are very accurate.
An excellent dealer in paper card models is http://papermodelstore.com
Books, there are a number of good books on railroad guns and armored trains. Search on eBay under those headings,and a number will appear for sale.
Remember the movie, Dr. Zhivago? There were scenes in a Russian Armored train in the movie. Aside from the good music and the train, the rest of the movie was kind of mushy, The good doctor sleeping with his girl friend who looked like she was eternally sucking on a rancid pickle. I like his faithful wife better.
The fun thing about armored trains is that one can really invent his own armored train. Many were created ad hoc in rail yards by railroad mechanics. It is a fascinating history.
in re aviation. I am working on a catapult mounted onto a railroad flatcar. The only problem is trying to figure out how to fold the airplanes wings so it all fits within the narrow clearances of a railroad line. These were used in the Vulgarian armed forces (located in the Balkans part of Europe) and also a cruder version was used by the Hawgwaller & Western Railroad (located in Appalachia, USA).
I like my models to move and although I may not make these 1/32 a/c flyable I will make all the trains run.