Trolley Locomotive Maintenance
There are some basic aspects regarding the maintenance of locomotive: 1. The inspection should be carried out at a fixed and exclusively-used place and only by a person in charge of the maintenance work. 2. No one should be nearby when the maintenance is undergoing. 3. Turn off the power. 4. Discharge in advance if there is a large-capacity electrolytic condenser in the speed controller. This shall be done by a qualified professional personnel trained by us.
Regular maintenance should be done to identify and solve problems on time.

A. Daily Maintenance of Trolley Locomotive
1. Brake shoe. (a) Clean the dirt on the brake shoe and the adjusting screw rod. (b) Check the wear condition. Replace the brake shoe if it less than 10mm thick and the gap between two brake shoes sharing the same brake rod is larger than 10mm. (c) Adjusting the brake shoe and make the space between the brake shoe and the wheel tread 2-3mm. The contacting surface should be no less than 60%.
2. Wheel. (a) Check if there is any crack and if the strake is loosen. (b) Check the depth of dent and abrasion. Immediately repair or replace the wheel thread if its dent is beyond 5mm and the flange is abraded more than 8mm in depth and 30mm in height.
3. Transmission gear. (a) Immediately repair or replace the gear if its abrasion is 25% beyond the original thickness. (b) Check the cover of gear cover, and fasten it if it loosens.
4. Spring. (a) Check if there is any crack and damage. (b) Clean the dirt. (c) Lubricate the hinge and the balance beam. (d) Stop the machine if the blade spring is fractured, and replace the fractured spring.
5. Check the fastening bolt, pin and split pin of each part. If it’s loosened or missed, fasten it or replace it with a new one.
6. Connecting device. Replace the damaged or abraded device.
7. Sand spraying device. (a) Unclog the sand pipe. (b) Adjust the position of sand pipe to make it align with the track center.
8. Lever and pin of the braking system. Check their flexibility and grease them.
9. Check the cable of the traction motor and the air compressor. Check the junction box.
10. Check the pressure of the air compressor system.
11. Temperature of the traction motor, bearing bush and bearing box. The prescribed temperature of the bearing and the bearing bush should be no higher than 75℃ and 65℃.
12. Light. Adjust the light angle and replace the damaged bulb.
13. Check the condition of the inner supply unit.

B. Ten-day Maintenance of Trolley Locomotive
Four-hour maintenance is required after running the trolley locomotive for ten days. This four-hour maintenance covers:
1. Exterior inspection and dust clean. (a) Carefully check the outer surface of mechanical parts and clean the dust. (b) For major equipment like speed controller, electrical motor, automatic switch, open its outer box to inspect and clean.
2. Add the lost fastening piece and connecting pin. Fasten the loosened bolts.
3. Replace the over-abraded brake shoe. Adjust the damper brake and sand spraying device.
4. Grease gear box, central axle box etc. as per standard.
5. Check the light and electrical whistle.
6. Check wheel set, plate spring and cushion device.

C. Minor Maintenance of Trolley Locomotive
After running the machine three months or 12500km, we need to carry out a 48-hour minor maintenance, which despite the content of ten-day maintenance, also covers:
1. Clean the spindle head and oil tank of the center axle.
2. Check and replace the bearing bush of the center axle.
3. Check the rotation of the wheel gear or replace the driving gear.
4. Lubricate all the motor bearings.

D. Medium Maintenance
After running the machine six months or 25000km, we need to carry out a ten-day medium maintenance, which despite the content of minor maintenance, also covers:
1. Electrical Parts
a. Disassemble the speed controller, automatic switch and electrical resistor, and clean each part. Repair or replace worn-out parts.
b. Repair or replace damaged wires.
c. Disassemble the electrical motor and clean its inner side. Dry clean the stator coil and rotor.
d. Repair the lighting device and check the meter.
e. Perform insulation resistance test to the electrical equipment and circuit.

2. Mechanical Parts
a. Repair or replace the wheel strake.
b. Repair or replace the axle.
c. Check and clean all the bearings.
d. Check and repair the connecting buffer.
e. Repair the abraded connecting rod and hinge of each part.
f. Disassemble the air compressor. Clean its parts, and repair or replace the abraded ones.
g. Disassemble the braking cylinder. Clean it and replace the sealing piece.
h. Repair the weld crack and local deformation.
i. Remove the rust and shed every year, and paint the locomotive.

E. Overhaul of Trolley Locomotive
After running the locomotive three years, a twenty-day overhaul should be carried out. Despite the content covered in medium maintenance, the overhaul also includes:
1. Replace all the electrical circuits and wires.
2. Disassemble all the equipment, and replace the one that does not function well.
3. Overhaul the traction motor or carry out a medium maintenance.
4. Bore the center axle’s bearing bush. Repair or replace the air compressor.
5. Repair the deformation.
6. Disassemble each part and clean it. Repair or replace the abraded parts.
7. Carry out pressure test to each electrical part.
8. Lubricate each part that needs to be lubricated.
9. Measure the braking distance every year. The braking distance should conform to the requirements of safety regulations of coal mine.