Air brake retarders are commonly used in mines. An air brake retarder is a device installed adjacent to the track or inside the hopper and reclaimer, used for stopping and positioning mining cars. The single-track car stopper consists of two parallel fixed brackets, a car stopper rod, a front bracket, a rear bracket, and a pedal linkage mechanism. The ends of the fixed brackets of the single-track car stopper are fixed to the front and rear brackets respectively. The car stopper rod is positioned between the two fixed brackets. A pivot shaft connecting the two fixed brackets passes through the middle of the car stopper rod. The car stopper rod has a heavier upper end and a heavier lower end. In its natural state, the upper end is inclined, and the pedal linkage mechanism is composed of a pedal and a pull cord.