After a short call for bids, the German State Railroad granted development contracts in 1943 for one of the last projects, which was already utopian for its time: a very heavy, fast freight locomotive for operation over long routes on rough terrain. The design presented by Borsig envisioned a Mallet design articulated locomotive with 4 cylinders. With an output of almost 3,000 horsepower and an axle load of under 20 metric tons, it would have been able to reach a speed of 80 km/h / 50 mph in both directions and pull a train of 1,700 metric tons over an 8% grade at 20 km/h / 13 mph, even on curves with a radius of 360 meters / 1,181 feet. The Borsig engineers were never able to prove these theoretical performance data; a working prototype was never built.
At the end of 1943 at least the running gear, the frame and boiler were supposed to have been built for the first unit of this immense locomotive; the large tender had not been built yet, however. The construction of such a prototype surely was a lesser priority than the ongoing production of other locomotives. At this time in Germany, for all practical purposes only the heavy class 42 locomotives and particularly the maneuverable class 52 locomotives were still being built in considerable quantities. Moreover, the war damage at Borsig in Berlin was so devastating that regular production was no longer possible - in 1944 just 2 more Borsig locomotives were finished. The current orders as well as many still usable machines and material were finally moved for the most part to Henschel in Kassel.
This gave new potential again for the project for the large Mallet locomotive. Instead of the high-capacity tender planned for the locomotive, the high demand for water for the four cylinders could also have been covered by the existing Henschel condensation tender, type 3´2´T16. The condensation process would also have enabled a synthesis of high performance and relative economy in this super large locomotive. The class 53 was never converted into a condensation locomotive; the required design changes for this secret project have also not been documented. Additional work and thought was probably finally stopped, when no more 5-axle tenders were available after the delivery of the first series of the class 52 condensation locomotives was completed. The locomotives that followed could only be equipped with the type 2´2`T13,5 tender, and this tender was much too small for the Borsig locomotive. So, it remained an idea, a second concept for the largest German steam locomotive, which after a pause in development of 63 years is still being realized at least in the scale of 1:220.