The Killen-Walsh Manufacturing Company (USA) made farm tractors. It changed its name to Killen-Strait in 1914, to build the agricultural tricycle Strait’s Tractor, designed by William Strait. The first version was powered by a four-cylinder Doman engine. It was known as the 30-50 model. The later version was called the model 3 15-30 tractor but had a less powerful engine. It was advertised as being able to pull two or three 14 inch ploughs.