Matching clearance between the road spike and the sleeper nail hole
- What is the standard for the clearance between the spike and the sleeper nail hole?
The clearance between the spiral spike and the concrete sleeper nail hole is 0.5mm~1mm; the clearance between the round head spike and the wooden sleeper nail hole is 1mm~1.5mm, which is convenient for installation and can ensure the anchoring force. The clearance of heavy-duty railway spikes is controlled at 0.3mm~0.8mm to reduce vibration loosening.
- What problems will arise from improper clearance?
Too small clearance (<0.3mm) will make the spike installation difficult, requiring strong knocking, and easily cracking the sleeper nail hole; too large clearance (>2mm) will reduce the anchoring force of the spike by 40%, the spike will shake when the train passes, and the loosening rate will exceed 50% within 6 months.
- How to detect the clearance?
Use a feeler gauge to measure the radial clearance after the spike is installed, and measure 3 points on each side to take the average value; or use a diameter gauge to measure the nail hole diameter and the spike diameter, and the difference is the clearance. 50 spikes are randomly inspected every kilometer, and those with excessive clearance need to be reworked.
- What are the common measures to adjust the clearance?
If the clearance is too small, the hole can be enlarged (special reamer is used for concrete sleepers) to enlarge the diameter of the nail hole by 0.5mm; if the clearance is too large, a thin iron sheet (thickness 0.3mm~0.5mm) can be wrapped around the spike, or a larger diameter spike can be replaced (such as the original Φ22mm replaced by Φ23mm).
- Are there any differences in the clearance requirements for spikes with different anchoring methods?
Sulfur anchor spikes require a clearance of 1mm~1.5mm to facilitate mortar filling; resin anchoring clearance is 0.5mm~1mm to ensure resin bonding; expansion spike clearance must be ≤0.5mm to ensure a tight fit after expansion without the need for additional filling materials.