5 Types and Specification of Rail Spike: Dimensions, Grades and Materials

What a Rail Spike Does in the Track Structure

A rail spike is the classic mechanical fastening element of a railway track. Screwed or driven through the rail base into a wooden or concrete sleeper, it restrains lateral, longitudinal and vertical movement of the rail while still permitting the small elastic movements the track needs under traffic. The traditional cut spike relies on an offset head, a flat edge and a chisel point that resist loosening; screw spikes add a helical thread and a washer so that clamping force can be regulated and re-tightened during maintenance. Both families are still produced because they are simple, economical to install and easy to maintain. Five product families cover most requirements: Ss series sleeper screw spikes, square head screw spikes, hexagon screw spikes, double-head screw spikes and dog spikes.

1. Ss Series Sleeper Screw Spike: Dimensions and Weights

The Ss series is the most widely used screw spike family for timber and concrete sleepers with pre-drilled dowels. Weight per piece is quoted for the finished, uncoated part and rises with diameter and length.

Model	Thread size	Weight (kg/pc)
Ss 1/130	M22×130	0.451
Ss 1/150	M22×150	0.478
Ss 2/180	M22×150	0.595
Ss 5/150	M24×150	0.545
Ss 6/150	M26×150	0.702
Ss 7/180	M24×180	0.636
Ss 8/140	M24×140	0.528
Ss 8/150	M24×150	0.548

Surface finish is normally natural, zinc-plated, painted or oiled, and the governing standard may be UIC, AREMA or GB, or the customer drawing. Smaller M22 models suit light and medium axle loads and easy re-tightening, while M24 to M26 models are chosen where higher extraction resistance is needed.

2. Square Head Screw Spike

The square head gives a large bearing area under the rail base and accepts a standard wrench, which makes it a practical choice for industrial and crane tracks as well as mainline sleepers.

Product	Specification	Material	Standard
Square head screw spike	M22×145	45#, 55Q, Q235	UIC / AREMA / DIN / GB
Square head screw spike	M22×155	45#, 55Q, Q235	UIC / AREMA / DIN / GB
Square head screw spike	M22×165	45#, 55Q, Q235	UIC / AREMA / DIN / GB
Square head screw spike	M22×185	45#, 55Q, Q235	UIC / AREMA / DIN / GB
Square head screw spike	M22×195	45#, 55Q, Q235	UIC / AREMA / DIN / GB

Other lengths and shank designs are produced to drawing or sample, and surface treatment follows the same natural, zinc, paint or oil options as the Ss series.

3. Hexagon Screw Spike: Property Classes and Mechanics

Hexagon screw spikes are specified by property class rather than by a single material, and the mechanical values below are minimum acceptance values for the finished fastener.

Class	Material	Tensile strength	Yield strength	Elongation
4.6	Q235	≥400 MPa	≥240 MPa	≥22%
5.6	35#	≥500 MPa	≥300 MPa	≥20%
8.8	45#	≥800 MPa	≥640 MPa	≥12%
10.9	40Cr	≥1000 MPa	≥900 MPa	≥9%

Cold bending of 90 degrees without cracking is required for the lower classes, which confirms that the head-to-shank transition has been correctly radiused and heat treated. Available finishes include plain oiled, oxide black, zinc plating, hot-dip galvanizing, wax, bitumen, dacromet and sherardizing; higher classes are normally supplied with a controlled coating to limit hydrogen embrittlement risk.

4. Double-Head Screw Spike

The double-head design carries a thread at each end and is used with a nut for adjustable clamping or where a through-fastening detail is required.

Size: 23×174

Property classes: 4.6, 5.6, 8.8, 10.9

Raw material: Q235, 35#, 45#

Surface treatment: plain oiled, bluing, zinc plating, hot-dip galvanizing

5. Dog Spike (Cut Spike)

Dog spikes remain the fastest manual fastening for timber sleepers and temporary or industrial track. Imperial sizes are still the practical reference in many markets.

Specification	Material	Standard
5/8×6 in	A3, Q235, 45#, 55#	To customer drawing or sample
9/16×5-1/2 in	A3, Q235, 45#, 55#
3/8×3-1/2 in	A3, Q235, 45#, 55#
1/2×3-1/2 in	A3, Q235, 45#, 55#

Surface Protection and Standard Options

Plain oiled: lowest cost, suitable for indoor or short-service track.

Zinc plating and hot-dip galvanizing: standard choice for humid, coastal and tunnel environments.

Paint and bitumen: used where colour coding or additional barrier protection is specified.

Dacromet and sherardizing: zinc-flake systems for high-strength classes where plating would risk embrittlement.

How to Specify a Rail Spike Correctly

Confirm the sleeper material and dowel type, because screw spikes cannot be used directly in unplugged concrete sleepers.

Define the clamping force and extraction resistance required by the axle load and curve radius.

Select the property class first, then the material that can reach it consistently after heat treatment.

State the corrosion category so the coating is fixed before quoting, not after.

Provide a drawing with thread tolerance, head geometry and acceptable coating thickness.

Frequently Asked Questions

Q: Are rail spikes still used on mainline railways?
Yes. Screw spikes and Ss series sleeper screws are still widely specified for timber sleepers and for concrete sleepers fitted with plastic dowels, especially on secondary lines, industrial tracks and crane rails.

Q: What is the difference between a dog spike and a screw spike?
A dog spike is driven with a hammer and relies on friction, while a screw spike is turned into the sleeper and can be removed or re-tightened without damaging the timber.

Q: Which grade should be used for heavy-haul track?
Property classes 8.8 and 10.9 in 45# or 40Cr are typical, because they combine high tensile strength with adequate elongation for repeated dynamic loading.

Q: Can the spikes be supplied to a custom length?
Yes. Lengths, thread sizes, head shapes and coatings are all produced to customer drawings or samples, and both UIC and AREMA reference dimensions can be followed.

Q: What coating is recommended for coastal areas?
Hot-dip galvanizing or a zinc-flake system is normally selected; plain oiled spikes should be avoided where airborne chlorides are present.

Q: How is quality verified before shipment?
Sample lots are checked for dimensions, thread gauge, mechanical properties, coating thickness and a 90 degree cold bend on the lower property classes.