Exhaustive Test
Use a hammer to tap each railway fish plate individually.
Identify untightened bolts by variations in sound.
Retwist bolts that show no twist upon examination.
Sampling Survey
Inspect the fastening axial force at every joint individually.
Select 10% of total joint bolts randomly for the survey, limited to less than two.
If bolts fail the initial check, repeat the survey with twice the number.
For non-compliant bolts:
For loose twist bolts, retwist with a torque 10% higher than before.
For tight twist bolts, replace them all.
Proper Fastening Order
Ensure a specific order for fastening bolts.
Avoid arbitrary fastening or focusing on one or two ends.
Prevent additional internal force and empty spaces on the rubbing surface due to uneven connection plates.
Maintain order to facilitate proper friction transfer.
