Brake vans, which date back to the earliest days of railways, were needed because for many years the only other brakes on a train were on the locomotive, and drivers could 'whistle for brakes' to the guard in the brake van if the train had to stop as quickly as possible.

Historically, trains used "brake vans" (or "cabooses" in North America) because early freight wagons were not equipped with their own braking systems. This meant that the only way to stop a long, heavy train was using the locomotive's brakes and the hand-applied brakes on a special van at the very end of the train. The Guard sitting in the brake van would listen for the driver’s whistle and manually crank a large wheel to apply the brakes, helping to keep the couplings tight and preventing the train from "running away" on downhill grades. Additionally, the brake van served as a safety marker; the Guard would watch for the "tail lamp" to ensure the train hadn't split in two. With the invention of continuous air and vacuum brakes in the late 19th and early 20th centuries—which allow the driver to apply brakes to every single wagon simultaneously from the cab—the mechanical need for brake vans disappeared, though they lingered in some countries until the late 20th century.