Complex sentence: In 1919, Stoughton Wagon Company (Stoughton, Wisconsin) had begun putting custom wagon bodies on Model T chassis; by 1929 Ford was by far the biggest seller of station wagons.
Split into simpler sentences: In 1919, the Stoughton Wagon Company of Stoughton, Wisconsin, had begun putting custom wagon bodies on Model T chassis. By 1929 Ford was by far the biggest seller of station wagons.