The R.H. Sheppard company built a line of farm tractors using their own diesel engine in the early 1950s in Pennsylvania. Sheppard manufactured diesel engines for a range of applications in the post-war period. In 1949, the Sheppard Diesel line of tractors was developed to utilize the diesel engines in farm tractors. Competition from the major tractor manufacturers, along with slow acceptance and cost of the diesel engine led Sheppard to stop tractor production in 1956 to focus on power steering equipment.
R.H. Sheppard - official site