The FQX class entered service during late 1960's. They were introduced to cope with the increasing amount of container traffic. Construction continued through to 1979. Number group was 501 - 935.
The South Australian Railways also built identical wagons coded FQX with numbers below 500.
During 1977, the numbers group 501 - 600 were planned for recoding to FQF_. The recoding was to reduce the number of bogie exchange vehicles in service.
A skeletal version of the FQX was built in the late 1970's and was coded QMX_.
In the 1979 recoding the FQX class became VQCX.
In 1980 another seventy five container flat wagons were built. These were VQCX 936 - 1010.
Wagons incorrectly coded FQF/VQCY were coded back to VQCX during 1980. These include numbers 508, 540 and 564.
During 1985, many of the VQCY wagons were reclassed back to VQCX.
In 1993 about seventy wagons were recoded to VQRF (R=Rice) to ensure sufficient wagons for the traffic between Echuca and Melbourne/Geelong.
In 1994/1995 the remaining VQCX wagons were placed into NRC traffic and relettered to RQCX.
By late 1995, early 1996, many RQCX wagons had been returned to Vline and recoded back to VQCX. NRC had begun replacing the wagons with new five pack container wagons.
Some wagons returned to Vline have remained in storage at country location.