The pilot reported that he was returning to his base from spraying sulfur on crop fields near Merced when the engine suddenly quit. The pilot set up for a landing on a highway, but discontinued the approach when he observed there were many vehicles on the road. The pilot landed in a railroad right of way and collided with fence and sign posts during the ground roll. FAA inspectors examined the aircraft. No fuel was found in the aircraft tanks, which were determined to be intact. Only minor traces of fuel were found in the lines and distributor manifold.