All British First Generation DMUs used the Gresham & Craven quick release twin-pipe vacuum brake system, with the exception of the railbuses which had air brakes.
Release of the brakes is entirely independent of the exhauster speed and is obtained through the medium of a 'release reservoir' which is exhausted while the car is running.
Also of note is the direct admission valve beside the brake cylinders, and the Passenger Communication and Guards Emergency Valve. When operated, these valves admit air into the train-pipe, giving a full brake application with no time delay.
Some types of DMU had this plaque fitted to drivers desk when new.