The class AX was recoded from _AF_ motor car transport. The group was numbered 1 - 22.
Between 1969 and 1972 the underframes were strengthened. Some records mention 'new underframe' in the modifications but observation of the same vehicles much later still showed truss bars and splice plates midway along the underframes. The modifications appear to have been new end sills and strengthened centre beams.
In the early 1970's, several wagons were allocated to 'Motorail' service between Melbourne and Mildura on the overnight passenger train. The remaining vehicles were on standard gauge in motor car traffic between Melbourne and Sydney.
The Motorail vehicle on the Mildura line service were numbered 2, 8, 9, 11, 17, 20. They were originally painted dark blue with white lettering. When the tangarine scheme was introduced in 1981 these vehicles were painted in the colour too.
The 1979 recoding saw the class recoded to VMAX.
Vehicles AX 8, 17 were reclassed to VMAY 1979/1980. Other Motorail cars were recoded to VMAX.
Between 1979 and 1980 the remaining wagons were relettered to VMAX.
In 1980, the Motorail wagons were reclassed to VMAY. These were VMAX 2, 9, 11, 20.
In 1991 all the wagons were in storage.
VMAX 7, 15 were scrapped in 1993.