The 56000 tender is derived from the BR44. Basically, German engineers reduced the weight of the tender by cutting down the coal and water capacity. They have also simplified its construction, most noticeably by using diamond bogies.
56086, elevated view of the tender.
The body of the Revel BR44 can be used as a starting point. This body has a nearly correct height and is about 5mm longer than required. The toolbox at the back end is also deeper than required. This can be fixed but I choose to keep it as it is, in part to keep the body in proportion with the bogies I had (see later).
On the tender body, the main change is to remove the ladders on the back ends. The sides of the body can be easily adapted to match the correct shape. The water tanks opening should be changed but this is tricky to do (I did not do it).
I choose to show a nearly empty coal bank. This lead me to built the bank from styrene sheets and place it inside the body. The only tricky part in this task is to fit properly the coal bank with the tender from end.
View of a trial assembly loco + tender before painting.
The Revel kit provides 3 parts for the frame:
The main problem is the bogies. If a spare pair of diamond bogies can be found, I strongly recommend to dump the Revel frame and bogies and go for a scratch built frame.
For the bogies, I used a pair of Ratio diamond bogies kindly supplied by John Treays. These bogies are a few millimeters too long. Otherwise, they are neatly engraved and can actually be used on an HO track. These bogies are supplied with plastic wheels and therefore are quite inexpensive. They are a perfect match for this project, which is intended to both simple and low budget.
The frame is simply done by a flat styrene sheet glued to the bottom of the body. The sides of the frame are done with a pair of U or H beam. The Revel rear buffer beam can be used. The front buffer beam must be scratch built. The Ratio bogies are then attached to this sheet. I used the support pieces provided by Ratio, but modified to bring the bogie as close as possible to the frame of the tender. The fit is a bit tight.
The look of the frame can be improved by adding the toolboxes that are below the body and next to the frame.
The final step is to add the footplate and detail the tender front end. Funnily, this footplate is missing from the Revel kit. It is easy to built one using a flat Styrene piece and adjust its height to that it matches the floor of the cab.
Tender superstructure is now finished; it is time to detail according to your taste and skills. In my opinion, the minimum is to create the ladders and steps and then do the coupling between the loco and the tender. The various hose and pipes can be done using copper wire glued to the plastic.
Finally, one can place those wood planks around to increase the capacity of the coal bank. This is not very aesthetic but typically TCDD.
56086, tender rear view, Ankara museum