Vehicles with track chains have not been widely used in farming or agricultural work as they have been in the military or in construction work. The relatively soft ground and the intensive buildup of dirt make bulldozers difficult to steer on a field, although the principle of a tracked vehicle enables high tractive effort at low motor power output. In the 1930s the so-called halftracks were supposed to link the advantages of this type of propulsion with the maneuverability of conventional tractors. Simple methods enabled the conversion of the halftrack Bulldog from Lanz: The rear wheels were replaced on each side by a tread; the rest of the running gear including front steering axle remained unchanged. This design was expensive despite the modular construction concept, and this vehicle found limited use away from farms. Production was halted in the 1950s, when more powerful diesel motors and improved drive systems using conventional axles became available.