Victorian Railways M class Wikipedia
The Victorian Railways M class were the first tank locomotives for suburban passenger service ordered by the Victorian Railways in Australia. They were numbered 40 (the prototype engine), 210-240 (evens only) and 312-320 (also evens only). They were classed M in 1886. Due to their small water and coal bunker → coal bunker capacity, they were not satisfactory on the longer suburban runs, and between 1901 and 1905 all were rebuilt as 4-4-2T locomotives with the frames extended at the rear to accommodate a radial axle to support an enlarged bunker of 3 tonnes (2.95 long tons; 3.31 short tons) capacity. As rebuilt, these locomotives were regarded as equal to the new E class 2-4-2T suburban engines, and the suffix E was added to the M. Although they were known as ME class the original M plates were not altered. None were preserved.