Understanding Railway Spikes
The railway spike is a traditional rail fastener used to secure the steel rail to the rail base and the sleeper. It has been used since the early days of railway construction and continues to evolve together with track technology. In China, the most commonly used railway spikes are screw spikes and dog spikes. These types are installed in different ways, but they all perform the same basic function of holding the rail firmly in position on the track structure.
Screw Spike Features and Technical Requirements
The screw spike gets its name from the thread formed on the surface of its shank. It is usually made of Q235-A steel. Compared with an ordinary dog spike, its pull-out resistance is about 0.5 to 1.0 times higher, but its thrust resistance is about 50 percent lower. Because disassembly and reassembly are less convenient, adjusting the gauge is more difficult, so screw spikes are generally applied at railway switches and turnouts where stronger holding is required.
Key technical requirements for screw spikes include: the upper thread is M24 and the basic dimensions must meet the requirements of GB 196, with thread tolerance manufactured according to 8g of GB 197; the end of the spike is manufactured in accordance with GB 2; forged burst cracks on the head surface must not extend to the shaft; the upper thread must be free of bumps and burrs that hinder assembly; the lower thread must be neatly shaped and complete without cracks; and the surface must be free of dents, burrs, flash, burns and scales that affect use. The screw spike must pass a physical tensile test and must not break when a load of 130 kN is applied.
Dog Spike Features and Technical Requirements
The dog spike, also known as a hook spike or cut spike, is mainly used to connect rails or rail pads to wooden sleepers. Ordinary dog spikes are made of hot-rolled carbon steel to GB standard. The cross section of the shank is a square of 16 mm on each side and the shank length is 165 mm. The head is mushroom shaped, and the lower part of the head is adapted to the shape of the rail base. The top of the spike is chisel shaped, and the chisel must be perpendicular to the wood grain to avoid splitting the sleeper.
Quality requirements for dog spikes include: the shank surface must be smooth and clean; the flash edge must not exceed 2 mm; displacement of the shank relative to the center line of the head must not exceed 1 mm in any direction; there must be no cracks at the joint between the head and the shank; and the surface must be free of air bubbles, excessive burns and cracks that hinder use.
Manual Spikes vs Mechanical Spikes
Ordinary dog spikes are divided into manual spikes and mechanical spikes. Manual spikes are produced by hot forming with a hand-assisted method and may carry surface convexities, burrs or weight variations. Mechanical spikes combine controlled production with strict standards, giving a smoother surface, more consistent weight and a lower defect rate, which makes them safer to transport and more suitable for batch use.
How to Choose the Right Spike for Your Project
Consider the sleeper type first. Screw spikes are preferred where high holding power is needed, such as switches, and where concrete sleepers are used together with plastic dowels. Dog spikes are the economical choice for wooden sleepers on lines with moderate loads. Choose mechanical spikes when product consistency and safety matter, and manual spikes when cost is the dominant factor on gentle, low-traffic sections. Always confirm the rail base dimensions, sleeper material, applicable standard and corrosion protection requirements before ordering.
Common Misconceptions About Railway Spikes
One common mistake is assuming that a more expensive spike is always better. In fact, an ordinary dog spike can be the most practical and economical solution on wooden sleepers with light traffic. Another mistake is mixing spike types on the same section of track, which can lead to uneven clamping and gauge variation. Some buyers also believe that all spikes are interchangeable between wood and concrete sleepers, but screw spikes normally need pre-installed dowels in concrete sleepers, while dog spikes are designed for wood.
Frequently Asked Questions
What is the difference between a screw spike and a dog spike? screw spike has a threaded shank and is screwed into the sleeper, while a dog spike has a square shank and a chisel tip and is driven in with a hammer.
Which spike has higher holding power? The screw spike offers about 0.5 to 1.0 times higher pull-out resistance than the ordinary dog spike, which is why it is used at switches and on demanding sections.
Can dog spikes be used on concrete sleepers? Dog spikes are designed for wooden sleepers. Concrete sleepers normally require screw spikes combined with plastic dowels or cast-in inserts.
Why is the tip of a dog spike chisel shaped? The chisel tip is aligned perpendicular to the wood grain so that the spike displaces fewer wood fibers and avoids cracking the sleeper during installation.
What surface treatments are available for railway spikes? Common options include plain oiled, black paint, zinc plating and hot-dip galvanizing, which protect the spike from corrosion in different environments.
What length of dog spike is standard? common standard dog spike has a 16 mm by 16 mm square shank and a length of 165 mm, while inch-series sizes such as 5/8 by 6 inches are also widely used.
