Back of IS-2 heavy tank, which was Soviet response to the Tiger tanks. Simpler design, new suspension, sloped armour - this made IS-2 far superior than Tiger.
Two of such vehicles were used in "Czterej pancerni i pies" series (episode 12, "Fort Olgierd") where they were playing two Konigstigers (or maybe captured IS-2, however since they were covered with German camo, I suppose they used them because there were no operational K-Tigers at the time). Also there was one BRDM-2 armoured reconaissance vehicle, playing German armoured car (possibly Sd.Kfz. 222).
In Museum of Polish Army you can see a lot of Russian stuff which was used by People Army of Poland (Polish Army under Communists command). This is usually called "gift from Soviet Army to the people of Poland". Such a gifts are usually obsolete equipment - tanks, planes, weapons - which were send to museum to reduce costs. You see, keeping such an old, useless tank in military base costs alot. If you send it to museum - problem solved.
EDIT: But of course not everything here is junk, some are very precious displays. And some are still working, for example BM-21 Grad is still in use, altough at never chassiss.
Piękny czołg, spora armata, gruby pancerz... i niesamowita ilość amunicji zabieranej ze sobą - sztuk 12 Oto cały IS-2 Niezłe zdjęcie ponadto, efekt psuje ten dopisek o darach z armii radzieckiej. Nie wiem skąd takie dane
Jednostki co przy wprowadzaniu nowego sprzętu się zostały, prawdopodobnie tak. Ale jakie wspaniałe zabytki nam się ostały Taki T34 to jeszcze często się spotyka,ale IS-2 albo taki KV-85 to już rzadkość. Zarabia raczej maszyna na siebie.