Which locomotive held the world speed record for a steam locomotive before Mallard?

Before Mallard, the DRG Class 05 002 held the world speed record for a steam locomotive.

On May 11, 1936, the streamlined German locomotive reached 200.4 km/h (124.5 mph) on the Berlin–Hamburg railway while hauling a 197-tonne train. It was one of three DRG Class 05 locomotives built by Borsig for high-speed express passenger service on the Deutsche Reichsbahn.

The record stood until July 3, 1938, when Britain’s LNER Class A4 4468 Mallard reached a higher measured speed. Mallard is usually recognized as the official record holder, although its run took place on a slight downhill gradient and caused bearing damage. The German run is often highlighted because it achieved 200.4 km/h on a level route without the same mechanical failure.

Another detail often missed is that 05 002’s record was a top-speed achievement, while the locomotive also set a separate start-to-stop record. Its Berlin-area run averaged 139.4 km/h over roughly 113 kilometres.