A traveling gear for an agricultural working machine configured to adjust an engine speed so as to control the traveling speed of the agricultural working machine for road travel. The traveling gear generally controls the traveling speed of the machine by controlling a central driving gear. The traveling gear generally includes a diesel engine as its central motive power source, a variable displacement pump driven by the diesel engine, an electro-hydraulic motor with an adjustable induction volume, and a pair of electro-hydraulic motors which are switchable in their induction volume. For a change in speed, the displacement volume of the variable displacement pump is adjusted. The change in displacement of the variable displacement pump causes a change in speed of the electro-hydraulic motors, which in turn causes a corresponding change in speed of the traveling gear and associated traveling speed of the agricultural machine.