The Victorian Railways M class were 4-4-0T (tank) steam locomotives for suburban passenger service in Melbourne, a pattern engine being supplied in 1879 by Beyer, Peacock & Company.

Twenty-one further locomotives of this model were built by the Phoenix Foundry of Ballarat, in three batches, from 1884 to 1886.

Because their relatively small coal bunker proved inadequate for the rapidly expanding suburban network of the 1880s, they were rebuilt between 1901 and 1905 at the Newport Workshops as 4-4-2T locomotives.

They were given an enlarged bunker of 3.05 tonnes (3.00 long tons; 3.36 short tons) capacity on extended frames supported by a trailing radial axle, and the cylinder diameter was increased from 17 to 18 inches (430 to 460 mm).

The last ME locomotives were scrapped in 1922, having been rendered surplus by the conversion of suburban lines to electric traction from 1919 onwards.