The invention relates to a control valve for indirectly acting compressed-air brakes of railway vehicles, containing a triple-pressure element (24) and a twin-pressure element (1), which comprises a control piston (2; 2'), on which from one side the pressure of the air of a main air line (L) acts and from the opposite side the pressure of the air of a valve spool chamber (S) acts and which interacts with an acceleration valve (6) via a tappet (5), which, in the open state, connects the main air line (L) via a check valve (12), and connects the valve spool chamber (S) via a valve (8; 8') or via a bore (9), to a channel (7), and further to a channel (13) for the additional ventilation at the start of braking via the triple-pressure element (24) and to a ventilation path (14) in the twin-pressure element (1) to the surroundings, wherein at least one throttle area (10) is arranged in the ventilation path (14), the effective cross-section of said throttle area being variable via actuation means in the twin-pressure element (1) from a closed or inactive state or from a minimum cross-section to a maximum cross-section.