Two sets of cylinders & motion [camera / lighting not playing fair].
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Jatibarang No.9 Mallet articulated locomotive.
Built 1930 by Arnold Jung in Kirchen, wks no 4878.

This is reputed to be the last Mallet, and the most powerful, to have been built in Germany.
She spent her working life in an Indonesian sugar mill.
After restoration she visited the Festiniog Railway in Nth Wales, allowing comparison with two other types of articulated locomotives - Fairlies and Garratts [Beyer-Garratt], also on 2ft gauge lines.