The QMDs were amongst the largest narrow gauge wagons to run on the W.A.G.R. They were 70'-0" long over headstocks and had two car decks for either 8 full cars or 12 car bodies. A total of twenty-three wagons were built in 1963 (20051-8), 1964 (20059-63) and 1966 (20064-73). They were, however, relatively short lived in their original form.

1971	20052, 20054, 20056, 20057, 20058, 20061, 20064, 20070, 20072 converted to QMG 20065, 20073 to QE 20051, 20053, 20055, 20060, 20062, 20063, 20066, 20067, 20068, 20069, 20071 written off
1972	20062, 20066, 20068, 20069 written back 20068 written off
1978	20062, 20066, 20069 written off

The WAGR outline diagram is shown below.