Wikipedia is a good reference for this one:
http://en.wikipedia.org/wiki/DRG_Class_86
775 examples being produced in the period from 1928 to 1943. Its area of operations was predominantly the routes in Germany's central mountains (Mittelgebirge)... ... The Bundesbahn stationed most of its 86's in Nuremberg for the Franconian branch lines and the marshalling yards there. The locomotive shed at Hof, Germany was also renowned Class 86 territory. ;


http://en.wikipedia.org/wiki/Prussian_T_20
Their areas of operations included the Sonneberg–Probstzella line, the Spessart ramp, the Franconian Forest Railway, the Geislingen ramp (Geislinger Steige), ... ...The locomotives were the most powerful tank engines procured by the DRG. They could haul a train load of 2060 tonnes at a speed of 50 km/h on the flat and could still manage 430 tonnes at 25 km/h on a 25‰ incline.


The best location would be as Tim points out the Thuringia region. The BR95 would climb and descend the coal mine while the other locomotives transfered coal to the mainline. You will need some open coal cars.

Best of luck.