The ZBA 'Rudd' is a type of low sided open wagon rebuilt from an older HTV type of coal hopper. This rebuild was done on behalf of the BR Civil Engineering department, the department responsible for maintaining the trackwork of the UK.
The ZBA was the most extreme of these rebuilt wagons with an entirely new body fitted as opposed to having the original one cut down. The first of these rebuilds began appearing in 1984, with the wagons becoming the longest lasting type. ZBA wagons saw their withdrawal come thick and fast around 2008, with their use diminished by advancements in wagon design in the 30 years they were in service.