Nothing is known about this train. The wagons had stars and marking CCCP on sides but the whole thing somehow does not look Russian. The point is not in the installed Pz.38(t) and Pz.IV late turret as it is quite possible that captured tanks were used to the purpose. Most likely, the Red Army acquired the whole train somewhere.
It looks to me that, while Pz.38(t) is installed on the platform as a tank, Pz.IV was used only partially. Note the flak installation on the front wagon (loco?).
Note the antenna on the Pz.38(t), marking CCCP/USSR and red star on the side of the platform.