Short answers, pulled from the story.
The Soviet Union and Germany established a joint tank school at Kazan in 1926. This secret agreement violated Treaty of Versailles restrictions on German industrial output.
Only about 7.2% of the 23,106 tanks possessed by the Red Army were modern models like the T-34 or KV-1 when Operation Barbarossa began in June 1941. Maintenance standards were poor and ammunition was in short supply during that period.
Thirteen PT-76 amphibious tanks assaulted approximately 24 Green Berets and 500 irregulars defending the position on the 6th of February 1968. These vehicles formed part of NVA 202nd Armored Regiment attacking the camp.
Egypt lost 820 vehicles including 82 T-55s during the conflict known as the Six-Day War which took place from June 5 to the 10th of June 1967. This loss occurred while fighting against Israel's 800 tanks.
The T-54 featured thickened front armor reaching 120 mm upper section and 90 mm lower section with a 100 mm D-10TK tank gun plus two 7.62 mm GWT machine guns. The new V-54 12-cylinder water-cooled diesel engine developed 520 hp at 2,000 rpm.