For dolomite traffic between Tantanoola, South Australia and the glass factory at Dandenong, Victoria, ten covered hopper wagons were built in 1974. They were gravity discharge, with top fill.
The wagons were coded JDX and the number group 201 - 210.
To reduce the number of bogie exchange wagons in service, the class was recoded to JDF in 1977.
In the 1979 recoding the class was relettered to VHDY.
VHDY 201 to 210 were reclassed to VHDX in 1987/1988.