The great need for locomotives in Germany during the second world war explains the explosion in production. First of all construction of classes 44, 50 and 86 was simplified, and orders for other types of locos were cancelled. The best loco of the war was the class BR 50. The construction of the Class BR 52 was not foreseen in any construction program, never mind that of 1939. In 1941 the need for a new simpler type was apparent. These machines became, with an axle load of 15 tonnes and a maximum speed of 80 km/h ( 44 mph ) forwards or backwards, as good as the Class BR 50. Significant quantities of materials and manpower were able to be reduced further reducing their cost.