Mallet type 0-4-4-0T (Malletlok) HSB number 99 5901 rests in the yard at Wernigerode between trips. The oldest HSB engine on their roster is Malletlok 99 5901-6 which was constructed for the Nordhausen-Wernigeroder Railway Company (NWE) as their number 11 in 1897. Mallet locomotives are named after the Swiss inventor of the drive system, Anatole Mallet (pronounced Anatohl Malleh). The first Harz Mallet, NWE 11, was built by Jung in 1897 at Nordhausen. It was followed by another 11 locomotives until 1901. At the beginning of the First World War the military impounded six Malletloks but none of them survived. Number 99 5906 was built for the army field railways then purchased in 1918 at the end of WWI. Today this engine is still operational on the HSB.