[3][4][5] Ostensibly built to provide rolling stock for the newly electrified Parramatta to Penrith section of the Main Western line, they operated across the Sydney suburban network.

[5] Overhauls of the stock continued up until 1988, with some receiving sliding aluminium Beclawat windows to alleviate rust problems.

Most of the trailer cars remained in service until the end of single deck operation in January 1992.

Sydney Trains has three Commonwealth Engineering Sputnik cars in the care of Historic Electric Traction.

On 8 May 2019, C3704 (Commonwealth Engineering (4 motor) Power Car) was removed from the Australian Technology Park and relocated to Taree to a private buyer.