The VBK class were First Class Saloon sitting cars for the Spirit of Progress train.
The cars were converted from _AZ_ cars in 1961. There were five cars, numbered 1 to 5.
The cars originally sat 48 passengers but between 1966 and 1969 the cars were modified to seat 56.
Between 1983 and 1987 the class was renumbered from 1 - 5 to 259 - 263.
From 1986 some cars were converted to ACZ_.