Ok ... might have sussed this ...
The figures are Foundry 28mm 2000AD minis.
As you can see on a standard slotta they fit into the open truck nicely.
The engine is about eight inches long. Carriages shorter.
I have glued some of the track to board ... each board is two feet long. Thr board on the right I have started to paint up ... and this is the first for me showing off my handiwork