Staatsspoorwegen class E10

The Padang coal railway on Sumatra was a rack line with a gradient of up to eight percent and curves with a radius of 150 meters. It was soon found out that the 0-8-2T locomotives of the D18 class were not powerful enough to haul 200-tonne trains. The solution was the 0-10-0T locomotive of the class E10.0 designed by the Esslingen Machine Works in 1916. Production only started in 1921 and until 1928, a total of 22 had been built by Esslingen and the SLM. Between 1964 and 1967, Esslingen and Nippon Sharyo built 17 more, which were designated E10.5.

They were of the Winterthur system, what meant that they had four equally sized cylinders working in compound. But the rack wheels were driven with a gear ratio of 1 to 2.033, so the low pressure cylinders moved at roughly twice the speed of the high pressure cylinders, eliminating the need for much larger cylinders. To allow operation on the sharp curves, the first and last driving axles had some side play.

Beginning in 1984, they were replaced by diesel locomotives. E1016 and E1060 were chosen for preservation, but there were only plans to keep the latter one operational. Although its rack mechanism was not compatible with the rack section of the Ambarawa railway, it often operated excursion trains in adhesion mode. After it suffered damage in 2016, it is on working order again since 2022.