From 1970 to 1972 the railways built fifty new steel bogie vans. The code allocated was ZF and the numbers were 1 - 50. _ZF_ had previously been used on vans which became the ZLP_ class in 1968.
These new steel ZF vans replaced ageing fixed wheel _ZL_ vans on freight trains.
In the early 1970's, vents were provided at floor level in the guards compartment area.
In the late 1970's, some vans were provided with crew compartments for crews travelling between depots. These vans feature a small sliding door to a crew compartment at one end.
In the 1983 van recoding, they were recoded to VVDY.
In 1983, the Vline logo began to be applied to rolling stock. In an unusual twist, the van ZF 17 was photographed with a Vline logo, one of the few, if not the only, rolling stock with an old code and a Vline logo.