A self-propelled harvesting machine includes a chassis supported on driven front ground wheels and steerable rear ground wheels. A crop harvesting attachment is supported on steerable driven wheels and is mounted to the front of the harvesting machine for pivoting about an upright axis. The harvesting attachment delivers harvested crop to an intermediate conveyor which feeds the crop to an input conveyor of the harvesting machine. The harvesting attachment includes a power operated steering actuator and is steered b a steering control device of the harvesting machine.
