Warflat_50t_3mm_27

This is a 3mm:1ft rescale of my 2mm later variant Warflat wagon. It comes complete with printed in-situ diamond frame bogies and printed in-situ 12mm gauge wheels. There is a fair chance that the wheels will turn and the bogies articulate straight off the production line, but the major advantage I see in printing as a single unit is that the price is probably lower than it would be as a bag of separate parts. If you need them separate, or to clean up the surfaces if they don't move freely, all you should need to do is to file off the little bumps on the ends of the bogie pivots, drop the bogies off, and flex the diamond frames gently to take the axles out. To be fair, you'll probably need to separate them like that to be able to fit couplings to them, unless you prefer to attach couplings to the body, and it will make painting much easier. 
Whether or not you take the bogies out first, do very carefully slice the stalks of brake handwheels off the underside of the body. Then separate them further and pick 2 of your choice, matching or otherwise, from 4 different designs, to fit on either ends of a piece of 0.30mm wire slid through the holes in the solebars for that purpose. The styles are 4 spoke (most common), 6 spoke,  5 curved spoke, and a smaller 4 spoke with outside handles. There are 4 of each, and in theory they have a tiny hole in the mddle of the hub (the stalk is hollow) to fit on the wire, though it may be clogged with debris. Keep the ones you don't use as spares, and for use on other projects.
Remove the rail jacks from under the headstocks (and file them down a bit at the front) if you don't need them on your model.
UPDATE 2024-01-21 Made the external-handles brake handwheel thicker for printability, but it may not be pretty enough. More importantly, added a NEM-355 box (like used on N-gauge) at 4mm above rail height, and adjusted the platform behind the dropper for this to 8mm above rail height (something to base your own system on, if you decide to cut off the NEMs). Whatever coupling system you use, the rail jacks may be a problem on curves.
UPDATE 2024-01-24 The previous update didn't "take" and also had a mistake anyway. Fixed that.
UPDATE 2024-01-29 The update on 24th "took" but _long story_ I'm having to upload exactly the same thing again hoping it overcomes a phreak in the processing of an outstanding order.
Feedback from the first version of the model (in tan fine detail plastic) was very positive, though the NEM pockets weren't quite right and the wheels break if mishandled. They spin freely when whole, though, and are very easy to remove and replace.
UPDATE 2024-03-02 Design improved slightly in several ways, most importantly the NEM pocket interior shape. Other changes have been to make the wheels and buffers a bit stronger and to make the pinpoints a bit tighter.
Many thanks to Paul Furner for sending me a "spare" print of the model, and photographs of the ones he painted and loaded.