it within the weight capacity of railroad flatcars. Although an experimental 15-ton tank, the M1924, reached the mock-up stage, this and other attempts to satisfy the War Department and infantry specifications proved to be unsatisfactory. In reality, it was simply impossible to build a 15-ton vehicle meeting both War Department and infantry requirements. In 1926, the General Staff reluctantly consented to the development of a 23-ton tank, although it made clear that efforts were to continue toward the production of a satisfactory 15-ton vehicle. The infantry were in agreement that a light tank, transportable by truck, best met their requirements. The net effect of the infantry's preoccupation with light tanks, and the limited funds available for tank development in general, was to slow the development of heavier vehicles and, ultimately, to contribute to the serious shortage of medium tanks at the outbreak of World War II. The real beginning of the Armored Force was in 1928, twelve years before it was officially established, when Secretary of War Dwight F. Davis directed that a tank force be developed in the Army, after observing the maneuvers by the British Experimental Armoured Force. Davis' 1928 directive for the development of a tank force resulted in the assembly and encampment of an experimental mechanized force at Camp Meade, Maryland, from 1 July to 20 September 1928. The combined arms team consisted of elements furnished by Infantry (including tanks), Cavalry, Field Artillery, the Air Corps, Engineer Corps, Ordnance Department, Chemical Warfare Service, and Medical Corps. An effort to continue the experiment in 1929 was defeated by insufficient funds and obsolete equipment, but the 1928 exercise did bear fruit, as the War Department Mechanization Board, appointed to study results of the experiment, recommended the permanent establishment of a mechanized force. Despite inadequate funding, the Ordnance Department managed to develop several experimental light and medium tanks, and also worked with auto engineer J. Walter Christie to test a Christie design model by 1929. None of these tanks were accepted, usually because each of them exceeded standards set by other Army branches. Patton later worked closely with Christie to improve the silhouette, suspension, power, and armament of the tanks. Christie's ideas had a great impact upon tank tactics and unit organization in many countries and, finally, upon the U.S. Army as well. On 21 November 1930, Douglas MacArthur had been made chief of staff, with the rank of