A working machine includes a working arm, the arm in use, carrying a working implement, the arm being raisable and lowerable about a generally horizontal axis by a power operated device, a cab structure for an operator, an engine for providing power to a ground engaging drive structure to drive the machine over the ground and for operating the working arm, each of the working arm, the cab structure and the engine being mounted on a machine chassis, and the machine being characterized in that the chassis includes a single primary chassis member which provides a substantial resistance to torsional deformation of the machine between the front and rear ends of the machine, the single primary chassis member including a first part which extends longitudinally of the machine at the one side of the machine, and a second part which extends transversely of the first part at or towards one end of the machine.