What are the 2 main types of rail spikes
Sep 30, 2025
In railway track fastening, the two primary types of spikes are dog spikes and screw spikes. The difference is not cosmetic: the two designs use different working principles, suit different sleeper materials and give very different holding power. Choosing the right type for the sleeper and traffic is one of the first decisions in any track project.
Dog spikes
A dog spike has an L-shaped head and a smooth, square or round shank. The head presses on the rail base and the shank is hammered into the timber sleeper, holding by the compressive friction of the sleeper fibres. Dog spikes are simple in structure, quick to install and low in cost, which is why they dominate timber sleeper track on low-traffic branch lines, industrial sidings and scenic railways. Their limits are equally clear: they work only in timber, they loosen as the timber compresses, and their vibration resistance is low.
Screw spikes
A screw spike has a threaded shank and a square or hexagonal head, and it is screwed rather than hammered. On concrete sleepers it engages an embedded plastic dowel or cast-in sleeve; on timber sleepers it grips a pre-drilled pilot hole. Installation is done with a torque wrench, and the long thread engagement gives superior pull-out resistance and fatigue performance compared with a dog spike. Additional anchoring with sulphur or resin compounds can raise the holding power further where required. Screw spikes are the standard fastening for high-speed railways, freight lines and urban transit systems with concrete sleepers.
Dog spike typical specification
| Item | Specification |
|---|---|
| Size | 23×174 mm (and other sizes per drawing) |
| Property class | 4.6, 5.6, 8.8, 10.9 |
| Raw material | 35#; also Q235, 45# |
| Surface treatment | Plain (oiled), bluing, zinc, hot-dip galvanizing |
Screw spike family
| Type | Raw material | Property class | Surface |
|---|---|---|---|
| Ss5, Ss8, Ss25, Ss36, UIC 864-1 series | Q235, 35#, 45#, 40Mn2, 20MnSi | 4.6, 4.8, 5.6, 8.8 | Plain (oiled), black paint, colour paint, zinc, HDG |
Head-to-head comparison
| Feature | Dog spike | Screw spike |
|---|---|---|
| Head design | L-shaped, presses on rail base | Square or hexagonal, with thread |
| Installation | Hammered | Screwed with torque wrench |
| Working principle | Friction of sleeper fibres | Thread engagement in dowel or timber |
| Sleeper types | Timber only | Concrete (dowel), timber (pilot hole), composite |
| Pull-out resistance | Lower | Higher; up to roughly twice a dog spike |
| Re-tightening | Not possible; must be re-driven | Possible; torque can be restored |
| Typical use | Light lines, yards, timber sleeper track | High-speed, heavy-haul, metro, concrete sleeper track |
How to choose between them
If your sleepers are timber and the line is light-duty, a dog spike is the economical, field-proven choice. If your sleepers are concrete or composite, or the line carries regular freight or passenger traffic, screw spikes with the matching dowel are required. For mixed situations, such as replacing timber sleepers with concrete on an existing line, plan the transition so that the fastening system and spike type change together at the sleeper replacement.
FAQ
Can a dog spike be used in a concrete sleeper?
No. A dog spike has nothing to grip in concrete. Concrete sleepers need screw spikes with embedded dowels or cast-in inserts, or elastic fastening systems with clips.
Why are screw spikes preferred on high-speed lines?
High-speed operation produces strong longitudinal and lateral forces and constant vibration. The threaded engagement of a screw spike holds the pre-load far better than a hammered spike, so gauge and fastening integrity are maintained between maintenance windows.
How much stronger is a screw spike than a dog spike?
In typical conditions a screw spike offers roughly twice the holding power of a comparable dog spike, and its pull-out resistance is about 0.5 to 1.0 times higher for the same size. The exact values depend on the dowel, timber species and installation quality.
What is a 23×174 dog spike used for?
The 23×174 mm size is a common dog spike for standard light and secondary rail on timber sleepers, where the rail base plate is fixed to the sleeper and the spike holds the plate and rail foot in position.
Do screw spikes need anchoring material?
Only where the fastening system specifies it. Sulphur or resin anchoring is used to fill the gap between the spike and the sleeper hole and raise pull-out resistance, mainly in timber sleeper systems. Concrete sleeper systems rely on the plastic dowel.
Can I mix dog spikes and screw spikes on one line?
Mixing is not recommended because the holding forces differ and the maintenance regime differs. Keep one spike type per line section, and change types only at a planned sleeper and fastening renewal.
