Brake vans were an essential fixture on freight trains where the continuous brake was not available. Loose-coupled wagons only had hand-operated ‘sprag’ brakes which had to be applied individually, for example, before descending a gradient. Trains were prone to broken coupling chains, so the brake van was essential for bringing a train to a halt under such circumstances. From 1968, the requirement for a brake van to be coupled to a fitted train (wagons with vacuum brakes) was removed from the rule book. BR adopted the LNER ‘Toad D’ van as the basis for its own standard brake van design.