The ELX class represented the largest block of bogie open wagon owned by the Victorian Railways (VR). Construction started in 1961 as ELF_, with new wagons built as ELX from 1964. Existing ELF wagons were recoded to ELX.
Numbers were 1 - 454, 1001 - 1104. The number block 501 - 1000 were allocated to similar type wagons operated by the South Australian Railways.
Part way through the ELX construction order in 1978, the class was altered to VOCX. Vehicles 1105 to 1170 were issued as VOCX class.
As part of this recoding, the ELX vehicles were split into two distinct groups: those fitted with standard tarpaulin support "ridge gear" were coded VOCX, and those either not fitted at all or fitted with non-standard "ridge gear" were recoded VOBX.
The railways altered the method of freight distribution in 1979. Small stations and sidings were closed and freight waybilled to major depots on each line. These depots were called "Freight Centres". For LCL (Less than Car Load) traffic a group of ELX/VOCX wagons were specially set aside and coded VOCY.
There were some basic construction types: flat sides, strengthened flat sides, corrugated sides, and corrugated sides with different coping along the "waterline" ( top of the sides ). Different methods of tarpaulin lashing bars were tried.
In the late 1970's, older style bodies were rebuilt with the construction style of the current wagon orders.