The Nordhausen-Wernigeroder Eisenbahn, better known for the Brocken Railway in the Harz mountains, got two Mallets from Borsig in 1922 and 1924. They had a 2-4-4-2 wheel arrangement and were fairly heavy for meter gauge. Due to the very short rigid wheelbase of only 1,300 mm (4 ft 3 in), they had insufficient running characteristics and tended to derail. Furthermore, they were not reliable.
In 1949, both were taken over by the Reichsbahn as 99 6011 and 6012. They were put out of service in the Harz in 1956. 99 6011 was brought to the Gera-Pforten–Wuitz-Mumsdorf line and only used there for a brief period. It was ultimately retired in 1966, as it had been the case with 99 6012 already in 1964. 