The WAGR M class was a class of 2-6-0+0-6-2 Garratt-type articulated steam locomotives operated by the Western Australian Government Railways (WAGR) between 1912 and 1955. A total of 13 were built by Beyer, Peacock & Co, Manchester in two batches.^[1]

The first batch of six engines was constructed in 1911. These engines, entered into service with WAGR in 1912, were only the third Garratt design to be produced and represented a significant step in the development of the type. The second batch, which consisted of seven units, was built in 1913/14 and designated as the Ms class due to the use of superheated steam. One of the engines from the first batch was retrofitted with a superheater and given a Ms classification.^[2][3]

All of the M/Ms class locomotives were utilized to haul trains on the WAGR's light lines. They were withdrawn from service between 1947 and 1955, and all were scrapped.^[1]

The M class designation was previously used for the M class locomotives that were withdrawn in 1911. It was reused in the 1970s when the M class diesel locomotives entered service.

• History of rail transport in Western Australia
• List of Western Australian locomotive classes