Some of these wagons were inherited from its predecessors, many were built new and some were acquired second-hand from the main-line railways.

The conversion consisted of building a small guard's compartment on one end of the flat wagon.

Therefore, these wagons could be used for carrying small items, such as sleepers, in addition to their role as a brake van.

Six brake vans numbered B580–5 were built for London Transport by British Railways (BR) at the latter's Ashford Works in the early 1960s.

[1] All data from London Underground Rolling Stock, 1st[2] through 15th[3] editions.