Why Screw Spikes Stand Out
Screw spikes have unique advantages over dog spikes due to their higher holding power, lower sleeper damage and reusability. Their threaded design provides a superior grip, approximately double that of a dog spike, and they do not split wooden sleepers during installation. They can also be easily unscrewed and reused, which makes maintenance more efficient. Screw spikes can be used together with spring washers, which further improves the stability of the fastening system.
Key Advantages Compared With Dog Spikes
The screw threads create a much stronger and more secure grip in the sleeper, providing more than twice the holding power of a dog spike. Unlike driven dog spikes, which can split wooden sleepers, screw spikes avoid this type of damage. Screw spikes can be unscrewed and reused in the same hole without damage, improving cost efficiency and making maintenance faster and simpler. Their reusability means they can be removed and retightened with a wrench, which reduces repair time. In addition, spring washers can be fitted under the head to resist loosening under vibration.
Screw Spike Types and Applications
In earlier practice, screw spikes were used mainly to fasten ribbed base plates and sole plates to wooden sleepers. With the development of concrete sleepers, screw spikes now play an important role in railway fastening systems with the help of plastic dowels. To meet different uses and standards, screw spikes can be classified into four main types: the Ss series sleeper screw, the square head screw spike, the hexagon head screw spike and the double-head screw spike.
Ss Series Sleeper Screw Spike
Typical Ss series specifications are shown in the table below. The thread size is expressed as the nominal diameter and length in millimeters.
| Type | Specification | Weight kg | Surface | Standard |
|---|---|---|---|---|
| Ss 1/130 | M22 x 130 | 0.451 | Natural, zinc, paint, oil | UIC, AREMA, GB or per drawings |
| Ss 1/150 | M22 x 150 | 0.478 | Natural, zinc, paint, oil | UIC, AREMA, GB or per drawings |
| Ss 2/180 | M22 x 180 | 0.595 | Natural, zinc, paint, oil | UIC, AREMA, GB or per drawings |
| Ss 5/150 | M24 x 150 | 0.545 | Natural, zinc, paint, oil | UIC, AREMA, GB or per drawings |
| Ss 6/150 | M26 x 150 | 0.702 | Natural, zinc, paint, oil | UIC, AREMA, GB or per drawings |
| Ss 7/180 | M24 x 180 | 0.636 | Natural, zinc, paint, oil | UIC, AREMA, GB or per drawings |
| Ss 8/140 | M24 x 140 | 0.528 | Natural, zinc, paint, oil | UIC, AREMA, GB or per drawings |
| Ss 8/150 | M24 x 150 | 0.548 | Natural, zinc, paint, oil | UIC, AREMA, GB or per drawings |
Other Screw Spike Types
Square head screw spikes are commonly supplied in M22 x 145, M22 x 155, M22 x 165, M22 x 185 and M22 x 195, in materials such as 45, 55Q and Q235. Hexagon head screw spikes are specially designed for fastening systems used on African railway lines and have very strict bending requirements, with the raw material straightened so that no crack appears after bending about 30 degrees. High-tension screw spikes for wooden sleepers are typically supplied in 15/16 by 6-1/2 inches with plain waxed or black painted surface.
How to Choose Between Screw Spike and Dog Spike
Use screw spikes when the line carries heavy loads, runs through switches and turnouts, or uses concrete sleepers with plastic dowels. Use dog spikes for wooden sleepers on conventional lines where simple hammer installation and low initial cost are preferred. If maintenance frequency matters, screw spikes win because they can be unscrewed and reused, while a driven dog spike must be pulled out completely before replacement.
Common Misconceptions
Some buyers think screw spikes are always more expensive to maintain, but their reusability usually reduces long-term cost. Others believe dog spikes have the same holding power, which is not true on most sleeper materials. Another misconception is that screw spikes cannot be used on wooden sleepers; in fact, they can be used with ribbed base plates and pre-drilled pilot holes. Finally, surface treatment is often overlooked, although zinc plating or hot-dip galvanizing is essential in humid environments.
Frequently Asked Questions
How much higher is the holding power of a screw spike? The screw spike provides more than twice the holding power of a dog spike in typical sleeper conditions.
Do screw spikes damage wooden sleepers? Screw spikes do not split wooden sleepers like driven dog spikes can, especially when a pilot hole is pre-drilled.
Can screw spikes be reused? Yes, they can be unscrewed and reused in the same hole without damage, which simplifies maintenance.
What is the Ss series screw spike? It is a common series of sleeper screw spikes, such as Ss 1/130 in M22 x 130, used with plastic dowels on concrete sleepers.
Where are screw spikes normally applied? They are used at railway switches, on heavy-load lines and on concrete sleeper tracks, typically with spring washers or plastic dowels.
