The project differed from most of the others in using several welded steel plate sections in addition to cast armour. In 1937 it became clear that the quality of cast armour was difficult to control and that limited production facilities, combined with the fact that many other French tanks used cast armour sections also, would restrict production. Also the Lorraine tank's electromechanical transmission was less of a development hazard; its suspension was that of the Lorraine 37L tractor and thus already in mass production. At the same time international tensions continued to rise; to have a modern type ready for introduction seemed a matter of simple precaution. As a result, in late 1937 the project was accepted for service and "Lorraine" was granted a full development contract for 2.6 million francs, with a prototype to be delivered before the end of 1938.