Railway Fastening Systems – 10 Common Questions Answered

1. What is the difference between a rail clip and a fish plate?

A rail clip holds the rail down to the sleeper. A fish plate connects two rail ends at a rail joint. Clips are used at every sleeper along the track; fish plates are used only at joints. Both are essential for a complete track structure.

2. How do I know if a rail clip needs replacing?

Look for these signs: red rust with pitting, visible cracks at the bend or toe, toe wear deeper than 2 mm, deformation or bending, or a clip that feels noticeably looser than a new one. If any of these appear, replace the clip.

3. What torque should I use for fish plate bolts?

For M22 bolts on standard 60 kg/m rail, use 500–600 N·m. For M24 bolts on heavy-haul lines, use 600–750 N·m. Always use a calibrated torque wrench. Do not rely on an impact gun set to "feel".

4. Why do fish plate bolts keep loosening?

The most common reason is that they were not re-torqued after the first week of service. Bolts settle under initial traffic. Also check if the bolts or threads are worn. Replace bolts and nuts as a complete set – new nuts on old bolts do not hold properly.

5. What coating should I choose for coastal railways?

For coastal or marine environments, use stainless steel clips and fish plates. If stainless steel is too expensive, choose a heavy epoxy coating with at least 1,000 hours of salt spray resistance. Standard zinc plating will not last in salt spray conditions.