Q: What are the advantages of screw spikes over cut spikes?
A: Screw spikes offer significant advantages:
Higher Pull-Out Resistance: The threads provide a much stronger grip in the sleeper.
Less Sleeper Damage: They do not split wooden sleepers like driven spikes can.
Reusability: They can often be unscrewed and reused in the same hole if undamaged.
Precise Installation Torque: They can be installed to a specific torque, ensuring consistent holding force.
Q: What are the international standards for rail spikes?
A: Different countries and regions have their own standards. Common ones include:
AREMA: American Railway Engineering and Maintenance-of-Way Association standards, common in North America.
EN Standards: European norms (e.g., EN 13479) for railway fasteners.
BS Standards: British standards.
IS Standards: Indian standards.
GB Standards: Chinese national standards.
These standards govern dimensions, material quality, mechanical properties, and coating requirements.
Q: How is the holding power or pull-out resistance of a spike tested?
A: Pull-out resistance is tested using a calibrated hydraulic or mechanical pull tester. The spike is installed in a test sleeper according to specification. The tester then applies an upward force until the spike pulls out. The maximum force recorded is the spike's pull-out resistance, a key metric for quality control.
Q: What role do rail spikes play in track circuit signaling?
A: In traditional tracks, spikes can cause signaling issues. Because they are metal and connect the rail to the ground (through the sleeper and ballast), they can create a short circuit, disrupting the electrical current used in track circuits to detect trains. Insulated sleeves or specially coated spikes are sometimes used in signaling zones to prevent this.
Q: What is a "spike driver" and how does it work?
A: A spike driver is a powerful, mechanized hammer used to drive cut spikes into wooden sleepers. Modern spike drivers are typically hydraulic or pneumatic tools mounted on track maintenance machines. They deliver consistent, high-impact blows to drive the spike quickly and to the correct depth, greatly improving efficiency and worker safety compared to manual hammering.