Budd–Michelin rubber-tired rail cars remained obscure in comparison with other competitors for the title, such as the "Pioneer Zephyr" and Union Pacific's M-10000. Rubber-tired rail cars achieved greater success in France, and similar rubber-tired subway cars have been adopted in Canada and Mexico as well as on numerous systems in Europe. During the 1920s, the American Budd Company, at the time a relatively obscure auto-frame supplier, developed an extensive working relationship with the French firm Michelin, which was best known for its tires. In 1929, Michelin built its first rail car, and by 1932 nine of its cars were in operating service, all of
International Rubber Regulation Agreement „Reichsverband der deutschen Kautschukindustrie”. Other countries, e.g. Japan or the Sowjetunion, had got no representation. The United States tried to become independent of the rubber cartel: establishing rubber plantations in territories under its control; conducting research into rubber-producing plants that thrive in the United States' climate; and reinvigorated efforts to replace natural rubber in tires with a synthetic. In the Fordlandia venture, Henry Ford failed in an attempt to produce rubber in Brazil. The Goodyear Tire and Rubber Company developed plantations in the Philippines and Costa Rica and Harvey Firestone developed plantations in Liberia. Research into synthetic rubber was limited