PNEUMATIC ANTI-COMPOUND ON SERVICE BRAKE BACKUP LINE

The disclosure relates to a pneumatic braking system comprising a service brake actuator; an electro-pneumatic modulator unit for receiving an air control pressure representative of a driver's braking request; delivering, by a regulation unit, a modulated air pressure to a service brake chamber; a parking brake actuator; a parking brake unit for delivering a second air pressure to a parking brake pneumatic chamber; and an isolation device for when the isolation device is electrically energized, preventing the delivery of the air control pressure to the regulation unit, and for when the isolation device is not electrically energized, allowing the delivery of air control pressure to the regulation unit when the second air pressure is higher than a threshold, and preventing the delivery of air control pressure to the regulation unit when the second air pressure is lower than the threshold.