A SYSTEM FOR CONTROLLING BACKUP AIR BRAKE FOR A LOCOMOTIVE

An air control backup brake control system of a locomotive, comprising: a backup brake valve, a balancing air cylinder, a relay valve, an air control stop valve, and a conversion plug; an input opening of the backup brake valve communicates with the first end of the conversion plug, and an output opening of the backup brake valve communicates with an air opening of the balancing air cylinder; the air opening of the balancing air cylinder and a pre-control opening of the relay valve communicate with the first end of the conversion plug, and the second end of the conversion plug communicates with a main air pipe; an air source opening of the relay valve communicates with the main air pipe, and an output opening of the relay valve communicates with an air inlet of the air control stop valve; the air outlet of the air control stop valve communicates with a train pipe, and a control opening of the air control stop valve communicates with the first end of the conversion plug; when the conversion plug is opened, the first end and the second end of the conversion plug are communicated with each other, otherwise, the first end communicates with the outside; and when a preset atmospheric pressure exists at the control opening of the air control stop valve, the air inlet and the air outlet of the air control stop valve are in communication with each other, otherwise, the air inlet of the air control stop valve is not in communication with the air outlet of the air control stop valve. According to the present invention, the balancing air cylinder is in a decompression state under normal conditions, so as to guarantee that the locomotive has a stable braking effect when performing pure air backup braking, avoiding the occurrence of a remission situation.