99.6001 was the first of a series of 2-6-2, 2-8-2 and 2-10-2 tank locomotives that were intended to modernise the metre gauge lines in the Harz. The loco was completed by Krupp in 1939 but WWII intervened before any more could be built. Attempts to procure similar locos during and after the war came to nothing.
The only member of class 9960 was photographed on shed at Gernrode on the evening of 10 October 2015, after it had finished its work on the Selketalbahn for the day.