Q: What is a rail spike and what is its primary function?
A: A rail spike is a large metal nail used to secure railway rails to wooden or concrete sleepers (ties). Its primary function is to fasten the rail baseplate to the sleeper, preventing longitudinal and lateral movement of the rail. It maintains correct track gauge and ensures stability by transferring the load from the rail to the sleeper and the ballast below. While largely superseded by more modern fastening systems on mainlines, they are still crucial for traditional tracks and specific applications.
Q: What are the main types of rail spikes?
A: There are several key types:
Cut Spike (or Dog Spike): The most common type for wooden sleepers, with a chiseled point and a head designed to be driven flush.
Screw Spike: Features threads along its shank and is screwed into a pre-drilled hole in concrete or wooden sleepers, providing superior pull-out resistance.
Elastic Spike: Has a spring-like design that provides a clamping force, often used in conjunction with a baseplate on concrete sleepers.
Drive Spike: A simpler nail-like spike for temporary tracks or less critical applications.
Q: What materials are typically used to manufacture rail spikes?
A: Rail spikes are predominantly made from medium-carbon steel, chosen for its strength and durability. To combat corrosion, they are almost always coated. The most common coating is hot-dip galvanizing (zinc coating). In highly corrosive environments (coastal areas, tunnels), spikes with thicker zinc coatings or alternative coatings like epoxy may be used.
Q: Why is galvanizing important for rail spikes?
A: Galvanizing is critical because it provides a sacrificial layer of zinc that protects the underlying steel from rust and corrosion. The railway environment is harsh, exposed to rain, snow, and chemicals. Corrosion weakens the spike, reducing its holding power and overall lifespan. A galvanized coating significantly extends service life and reduces maintenance costs.
Q: What is the standard size and dimension of a typical cut spike?
A: While dimensions can vary by standard and region, a typical cut spike for a wooden sleeper might have a shank diameter of 16-20 mm (5/8" - 3/4") and a length of 100-150 mm (4" - 6"). The head is usually square and flat, designed to be driven flush with the baseplate or sleeper surface.