The state railway of the Dutch East Indies on Java had the challenge of moving heavy loads on cape-gauge mountain routes with a maximum axle load of 9.5 tonnes and curve radii of up to 140 meters. To solve these requirements, Hanomag proposed a tank locomotive with six coupled axles in one frame in order to be able to avoid building a Mallet with its disadvantages. Among these disadvantages were listed the tendency to slip, flexible and long steam lines, greater complexity of the running gear and unstable mounting of the boiler.
In the locomotive developed as a result, the four inner coupled axles were all firmly mounted in the frame. Only the first and sixth coupled axles could be moved laterally by 30 mm according to the Gölsdorf system, and the leading and trailing axles could be deflected laterally by 100 mm as Adams axles. The water tanks were drawn low between the frames in a new way. Now the boiler could be placed higher without raising the center of gravity to improve accessibility for maintenance.
Schematic drawing with dimensions
Locomotive Magazine, August 1912
The last batch was built by Werkspoor in the Netherlands. The total of 24 examples built were the first of only two types with the axle configuration 2-12-2T in history, which is why this wheel arrangement is also known as “Javanic”. On the route for which the locomotives were developed, there was a high level of wear on the wheel flanges. They were then moved to another mountain route that had bigger curve radii. There they did very well.