Train wheel maintenance involves several key procedures to ensure the safety and performance of the wheels:

1.Tread Wear Inspection
The standard diameter for train wheels is usually 860 mm, with a wear limit of 790 mm. Flange height is checked using a flange gauge, with the maximum allowable height being 33 mm. Flange thickness is also measured, with a minimum requirement of 26 mm. Wheel diameter differences are measured using a wheel diameter gauge at a specific point, and the allowable differences are as follows: within the same wheel ≤0.5 mm, within the same wheelset ≤1 mm, within the same bogie ≤4 mm, within the same vehicle ≤10 mm, and between vehicles ≤40 mm. The measurement is taken three times, and the average is used for inspection.

2.Inspection of Tread Scuffs, Rolling Marks, and Spalling
Scuffs, rolling marks, and spalling on the tread are inspected using a steel tape along the circumference of the wheel. The limits for these defects are as follows: scuff depth should be ≤0.5 mm, and length ≤70 mm; continuous rolling marks should be ≤70 mm; spalling at one spot should be ≤20 mm, and at two spots ≤10 mm each. If the wheel has rolled over foreign objects, and the continuous rolling mark is within 70 mm, the wheel may continue to operate. More severe spalling or damage may require re-profiling of the wheels.

3.Inspection of Wheel Inner Side Distance
The connection between the wheel and the seat is checked for looseness. If any looseness is detected, the wheel must be disassembled and reassembled with properly selected parts.

4.Ultrasonic Inspection of Rim and Web
Ultrasonic testing of the wheel’s rim and web is performed using specialized equipment. The wheels are first cleaned of debris, and their surfaces are inspected for defects. The inspection trolley is moved to the appropriate location, and the inspection is conducted. Sensors and magnets are placed on the wheel rim, and the inspection data is recorded and analyzed. The inner side distance of the wheels is measured to ensure it meets the standard of 1353mm.