In 1943 Germans, by "simplifying" the modern class 50, developed the robust "war locomotive", class 52. Nearly 6300 were produced, even in loco factories in occupied areas. A record output on one single day was 51 units. Because of moderate axle load and high top speed in both directions (!) they could be employed both on branch lines as well as for fast passenger trains. 25 locos were delivered as class 30 to the "Independent State of Croatia". After the war they were reclassified as JŽ-class 33. In spite of the fact that they were developed only for the duration of the war, they remained in service all over Europe until the end of the steam era. On the JŽ-network there were as much as 342 locos of this class on duty, finally in the sixties some came to Slovenia, to Ljubljana and onto the Bohinj line. Source: Railway Museum Ljubljana
