Tank
With World War II the multi-turreted tanks proved impracticable, and as the single turret on a low hull design became standard, crews became standardized around a crew of four or five. In those tanks with a fifth crew member, usually three were located in the turret (as described above) while the fifth was most often seated in the hull next to the driver, and operated the hull machine gun in addition to acting as a co-driver or radio operator. Well-designed crew stations, giving proper considerations to comfort and ergonomics, are an important factor in the combat effectiveness of a tank, as it limits fatigue and speeds up individual actions.
Tank corps (Soviet Union)
On 31 March 1942, orders were given for the reformation of the tank corps, as a result of the Soviet need for massed armored units so that the small tank brigades, which were now the basic armored formation, could be capable of decisive actions. The 1st, 2nd, 3rd, and 4th Tank Corps were to consist of a headquarters, two tank brigades, and a motor rifle brigade, authorized a total of 5,603 men with 20 KV heavy tanks, 40 T-34 medium tanks, and 40 T-60 or T-70 light tanks. The new tank corps lacked artillery, reconnaissance and engineer units, and rear support elements, although its component brigades included such formations. They were the equivalent of small Western armored divisions. The motor rifle brigade was a new unit type intended to retain captured positions and to neutralize enemy infantry and anti-tank weapons.