That should be in January/February 1943, during the evacuation of Caucasus, after the defeat in Stalingrad. There were several Panzer formations taking part in the operation and the train could belong to one of them. Armoured trains saw a wide use in the Eastern Front.
In the defence of the Rostov-Batajsk bridgehead and later during its evacuation, the train would be defending the railway and covering the retreat. The control of the railways was very crucial in a vast land with no advanced road system.
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