 A. Morozov in a short space of time gained considerable experience, reached the level of the chief designer, began to direct design group and since July 1936 headed sector of CB on new designing.In the second half of the 30th years the task on substantial was increase of shell firmness of armored corpus of tanks and increase in their survivability in the battlefield was set for designers of the factory.Designing of the wheel-caterpillar A-20 tank with increased, in comparison with the BT tank, quantity of the leading wheels skating rinks and with the case and a tower of an original form was one of important developments of that period.