Just a few more details for those asking
Size of the set up is a double bed size
However with an impending arrival at the end of the year I will be evicted from said space to make room for +1, so am making hay while the sun shines
The flatbeds and depressed centre flat cars was from USA trains, which I got from ebay store marmon927. (Efficient seller) (the rest of the rolling stock, the carraige, gondolas and low sided flat cars are 2nd hand Marklin Maxi which come up regularly enough on ebay and go very cheaply from american sellers- ,not german sellers though where marklin is extermemly popular)
USA Trains G Work Flat Car with Load Maintenance of Way (The attachments are detachable to give you a flat car with sides up for half the length.)
USA Trains G Truck Car Maintenance of Way gray (again the attachemnts detach giving you a flat car without any sides).
Marklin did have some WWII era heavy duty flat cars , but these are as collectable as K&C S/L editions and were way too expensive for my budget The american rolling stock was in use on both the western and eastern fronts through lendlease and I have a dvd which showed the US engineers assembling rolling stock in France, a tremendous amount of loco's and rolling stock was produced for both fronts.
I spray painted the cars using Tamiya spray cans -german grey on one side and the other a combo of dark yellow, red brown and olive drab2.The decals came from Archer transfers , (great tip from Alex). The tracks are a mixture of verlinden tracks and marklin maxi gauge one tracks. (my next step is to figure out how the transformers etc work and actually get it going)
Its certainly a lot of fun, the next thing I'd like to do is a winter train scene,and maybe get the train set actually rolling But that won't be for another while