The Lanz Bulldog D3506 is a farm tractor produced by Lanz from 1937 to 1942 as part of the D35 Series. It features a 4.7L single-cylinder liquid-cooled diesel engine producing 19.6 hp (14.6 kW) at 760 RPM. The tractor has a 6-speed gear transmission and 2WD drive. It was built in Mannheim, Baden-Württemberg, Germany. Variants include the D3500 with 3-speed, the D3506 with 6-speed, and the D3507 with 6-speed and lights.