The WR 550 D 14 was built as the largest of the Wehrmacht locomotives, which had four axles and an engine power of 550 hp. In terms of appearance, it largely corresponded to its three-axle sister, but was 1.5 meters longer and looked a bit beefier, mainly because of the thicker frame. The biggest difference was that the four wheel sets were all closely spaced and the jackshaft was at the rear end instead of in the middle. As with the WR 200 B 14, slightly different versions with different engines were planned depending on the manufacturer. These were the BMAG version with a six-cylinder MWM engine, the O&K version with a six-cylinder from MAN and the Deutz version with their own eight-cylinder.

Due to the bottlenecks during the war, only one example of each of the three types was produced. Two of them fell into British hands during the war in North Africa and were scrapped after a few years of further use. The O&K locomotive was a special case, which was converted to the so-called “Panzertriebwagen Pz.TR.Wg. 16” (tank railcar) in 1943. For this purpose, the locomotive was completely encased in armor and an armored trailer with four axles was attached to both ends. A rotating turret with a cannon was installed on each of these carriages, there are also photos with anti-aircraft quadruplets. The vehicle came to Poland after the war and was allegedly used there against insurgents. Today it can be seen in Warsaw in the Railway Museum.