The Dm class came about due to pressures resulting from aging and overworked motive power which was already understocked. The Dm class were based on the D class suburban tank engines and were constructed from E class tender engines. They operated commuter services in Perth and performed banking duties along the Midland to Chidlow section of the Eastern Railway. The first of the class was withdrawn in 1968 and the last in 1971, with all being scrapped.
