The Metropolitan Carriage & Wagon Co., Ltd., supplied twelve of this series in 1911, all of which have been scrapped.  Described as the "improved" type.  M.51 was the first to be scrapped, as early as 1951, followed by M.45 in 1971 with the remainder disposed of during the Ballasalla Bonfire of 1974.  The last to survive in use was M.47 for transporting and storing coal around the yard at Douglas Station, last being used in 1969 for this purpose.

The first three were replacement wagons and therefore the second vehicles to carry the numbers M.43, M.44 and M.45, the first three having been inherited from the Manx Northern Railway upon the 1905 merger and rebuilt into "M" wagons; these were then converted to cattle vans in 1908, namely M.43 was rebuilt to become K.11, M.44 into K.21 and M.44 to K.10, details of which can be found in the respective directories elsewhere on this site.