WORKING MACHINE

A base assembly for a working machine. The base assembly comprising a ground engaging structure, an undercarriage connected to the ground engaging structure, and a connector for connecting the undercarriage to a superstructure that mounts a working arm. A drive arrangement is provided for moving the ground engaging structure to propel, in use, the base assembly and a connected superstructure. The drive arrangement includes a prime mover and a transmission and the drive arrangement is housed within the undercarriage. An electronic control unit (ECU) is provided for controlling the drive arrangement and/or the ground engaging structure.