The earliest vehicles built featured catching nets and collection arms, to allow mail bags to be exchanged without the train needing to stop, a practice which continued until 1971.

Following the Great Train Robbery, vehicles from 80319 onwards featured a revised design with smaller windows.

In the early 1970s, British Rail introduced the TOPS classification system.

Vehicles were given the TOPS code NS, followed by an A if they were air-braked, V if vacuum-braked, or an X if they had both air and vacuum brakes.

Several sorting vehicles have been preserved, including examples from most of the big four companies, as well as some from even earlier.