DEVELOMENT

American tracked tractors in Europe

Benjamin Holt of the Holt Manufacturing Company of Stockton, California was the first to patent a workable crawler type tractor in 1907.^[10] The center of such innovation was in England, and in 1903 he traveled to England to learn more about ongoing development, though all those he saw failed their field tests.^[11] Holt paid Alvin Lombard US$60,000 ($1,533,111 in 2013) for the right to produce vehicles under Lombard's patent for the Lombard Steam Log Hauler.^[12]

Holt returned to Stockton and, utilizing his knowledge and his company's metallurgical capabilities, he became the first to design and manufacture practical continuous tracks for use in tractors. In England, David Roberts of Hornsby & Sons, Grantham, obtained a patent for a design in July 1904. In the United States, Holt replaced the wheels on a 40 horsepower (30 kW) Holt steamer, No. 77, with a set of wooden tracks bolted to chains. On November 24, 1904, he successfully tested the updated machine plowing the soggy delta land of Roberts Island.^[13]]

A Holt tractor in the Vosges during the spring of 1915 serving as an Artillery tractor for the French army.

When World War I broke out, with the problem of trench warfare and the difficulty of transporting supplies to the front, the pulling power of crawling-type tractors drew the attention of the military.^[14] Holt tractors were used to replace horses to haul artillery and other supplies. The Royal Army Service Corps also used them to haul long trains of freight wagons over the unimproved dirt tracks behind the front. Holt tractors were, ultimately, the inspiration for the development of the British and French tanks.^[13][15] By 1916, about 1000 of Holt's Caterpillar tractors were used by the British in World War I. Holt vice president Murray M. Baker said that these tractors weighed about 18,000 pounds (8,200 kg) and had 120 horsepower (89 kW).^[16] By the end of the war, 10,000 Holt vehicles had been used in the Allied war effort.^[17]

Fully tracked caterpillar tractors became commercially available in 1908, especially in the United States, but also in lesser quantities in Europe, and were to prove a solution to the cross-country requirements of World War I battlefields.^[1]:35 Over the next four years, they became a major artillery tractor, mainly used to haul medium guns like the 6-inch howitzer, the 60-pounder, and later the 9.2-inch howitzer.^[18]

By 1916, about 1,000 of Holt's Caterpillar tractors were in use by the British on the Western Front. By the end of World War I, the British War Office had received 2,100 Holt tractors,^[19] about 1,800 of the Holt Model 45 "Caterpillars"; 1,500 of the Holt Model 75 "Caterpillars", and 90 of the Holt six-cylinder Model 120 "Caterpillars", about one-eighth of approximately 5,000 Holt vehicles used by all Allied forces.^[20] Imported Holt tractors also formed the basis of the French Schneider and Saint-Chamond tanks and the German A7V tank.^[21]