FIELD: brake systems. SUBSTANCE: invention relates to automobile and tractor trains and can be used in the design of brake systems for trailers. The overrun brake of a single-axle trailer has working brake cylinders, which are kinematically connected to the running wheels of the trailer through brake drums connected to the hubs of the trailer running wheels by means of friction overrunning clutches, ensuring the transmission of torque from the hubs of the running wheels to the brake drums when the road train moves forward, while the internal races of the overrunning clutches are fixedly connected to the hubs of the trailer's road wheels, and the outer races are fixedly connected to the brake drums. EFFECT: development of a rollover brake for a single-axle trailer, the kinematic diagram of which ensures unhindered movement of the road train in reverse without first forcibly disabling the trailer's rollover braking during manoeuvring. 1 cl, 3 dwg.