Staatsspoorwegen classes 520 and 550

The class later known as CC10 consisted of 33 Mallet tank locomotives with a 2-6-6-0T wheel arrangement. They were ordered when the 0-4-4-2T class BB10 needed a more powerful successor in mixed traffic on the hilly and winding lines on West Java. The high pressure cylinders on the rear group of drivers had a diameter of 340 mm, while the low pressure cylinders in the front measured 520 mm. All cylinders had a stroke of 510 mm and the drivers had a diameter of 1,106 mm, or 1,112 mm according to some sources. They delivered an output of 680 hp. 

Like the BB10, the initial batches were built in Germany. The first 13 were built by Hartmann of Chemnitz in 1904 and 1905, followed by six built by BMAG in Berlin in 1907. In 1909, Hartmann delivered four more. In 1910, Werkspoor built ten more. The German locomotives were numbered 312 to 316, 329 to 336 and 355 to 364, while the Dutch ones carried the numbers 367 to 376. From 1912 they became 521 to 543 and 551 to 561. The class designation CC10 that is better known today was only given to them when the Japanese invaded Indonesia in 1942. Their direct successor was the class 800 or F10 that was built as a 2-12-2T without an articulated chassis and flexible steam lines.