PURPOSE: To ensure braking in a multi-disk braking device for a train, by coaxially installing a set of metallic disks actuated by a first pressure device and a set of carbon disks actuated by a second pressure so as to immediately actuate the metallic disks when stopping the train and to operate the carbon disks when an electrical retarder is abnormal.

CONSTITUTION: A braking device 1 is equipped with a set of metallic disks 4 and a set of carbon disks 5 coaxially on an axis 2, which are respectively connected to pressure devices 6 and 7 and actuated independently. When a speed sensor CA senses that a train has been slowed down to a speed limit by actuating an electrical retarder RE to put on the brake, a pressure device 5 is actuated through a control logic device LA and an electrical hydraulic directional control valve DI, so that the metallic disks 4 stop the train. A pressure device 7 is actuated to operate the carbon disks 5 when a detector DE detects that the electrical retarder RE is abnormal. Thereby, the brake is effectively applied until the train is stopped.