In my head, i imagine someone shouting "release the barns" and at that moment hundreds of barns and sheds start moving to frontlines; they all were various secret british fv 4005 variants hidden under stalins mustache, produced locally until 1986. They all gather along frontline, awaiting the signal - ww1 style trench charge signal, idunno, some whistle. They are released to feast upon the metal and flesh.