Ss8 Ss25 Ss35 Rail Screw Spikes Manufacturer | Signum Rail

Source UIC864-1 compliant Ss8, Ss25, and Ss35 rail screw spikes from Signum Rail Fasteners China. Premium Grade 5.6 & 8.8 track fasteners with 60kN+ pull-out.

In modern permanent way engineering, securing timber, composite, or concrete sleepers requires threaded fasteners that can withstand immense dynamic stress and massive vertical loads. As a leading global manufacturer, Signum Rail Fasteners China produces premium-grade Ss8, Ss25, and Ss35 rail screw spikes engineered to maintain precise track gauge and prevent longitudinal rail creep.

This technical article provides an in-depth breakdown of the dimensional specifications, manufacturing standards, and mechanical performance metrics of these three critical track fasteners.

Technical Standards for the Ss Series Screw Spikes

The Ss Series represents one of the most widely deployed track fastening standards in international railway networks. Precision-forged to meet the rigorous requirements of the international UIC864-1 standard, these threaded spikes are designed for high-stress environments like heavy-haul freight corridors and high-speed transit lines.

Unlike smooth track spikes, the roll-threaded design of the Ss series cuts a deep, permanent mating thread into wooden sleepers or embedded HDPE plastic dowels. This mechanical lock provides superior pull-out resistance and completely eliminates the risk of "spike killing" (the progressive degradation of sleeper fibers caused by friction).

Deep-Dive: Ss8 vs. Ss25 vs. Ss35 Technical Profiles

While all three screw spike models feature a standard M24 outer thread diameter and a 12.5 mm thread pitch, they vary in length and architecture to fit specific sleeper types and rail baseplate configurations.

1. Ss8 Rail Screw Spike: The Global Baseline

· Primary Application: Heavily utilized in standard track systems, ribbed tie plates, and timber sleeper turnouts.

· Standard Lengths: Available in 145 mm and 165 mm variants.

· Key Benefit: Provides a compact, highly efficient footprint that balances excellent holding power with fast installation times on secondary and mainline tracks.

2. Ss25 Rail Screw Spike: Optimized for Concrete Infrastructure

· Primary Application: The preferred choice for modern pre-stressed concrete sleeper assemblies.

· Standard Length: Standardized at 185 mm.

· Key Benefit: Engineered with an extended unthreaded shank that perfectly accommodates the depth of cast-in plastic dowels, creating a completely watertight, debris-resistant seal inside the concrete tie.

3. Ss35 Rail Screw Spike: Maximum Heavy-Haul Anchor

· Primary Application: Deployed on extreme curved track sections, sharp turnouts, and heavy-freight networks subjected to immense lateral thrust forces.

· Standard Length: Extended length of 215 mm.

· Key Benefit: Features a deep thread length of 115 mm, providing maximum pull-out resistance and anchoring depth when the structural stability of the entire track bed is critical.

Quick-Reference Blueprint Matrix

Mechanical Performance Data and Material Properties

Every production lot leaving the Signum Rail Fasteners China factory undergoes rigorous destructive and non-destructive laboratory testing to satisfy global quality assurance benchmarks.

Forging Materials and Strength Grades

Signum fabricates the Ss series utilizing premium medium carbon steel or custom alloy steel formulations. We supply hardware matching multiple strength classifications depending on your tender requirements:

· Grade 5.6: Provides an optimal balance of elasticity and yield strength for standard track applications.

· Grade 8.8 High-Tensile: Engineered for heavy-haul lines, delivering a minimum tensile strength of 800 to 1000 MPa and a yield strength of ≥ 640 MPa.

Laboratory Pull-Out Resistance Tests

When tested in standard high-density polyethylene (HDPE) dowels using calibrated hydraulic tensile machinery, our screw spikes safely exceed international safety margins:

· Minimum Industry Standard Requirement: ≥ 60 kN

· Signum Batch Test Average: 75 kN to 92 kN before thread shear or concrete blowouts occur.

· Fatigue Limits: Verified to withstand 2 million cycles of dynamic loading without exhibiting structural micro-cracking.

Premium Finishes for Harsh Track Environments

To protect tracks from environmental hazards like coastal salt air, tunnel humidity, and chemical pollution, Signum offers three heavy-duty surface finishes:

· Plain Oil: High-viscosity rust-preventative coating for cost-effective short-to-medium-term protection during transit and warehouse storage.

· Black Oxide: A sleek chemical conversion coating offering budget-friendly corrosion resistance with zero impact on precise thread tolerances.

· Hot-Dip Galvanization (HDG): A thick, metallurgically bonded zinc layer (≥ 500 g/m²) that delivers ≥ 720 hours of salt spray resistance—making it the definitive choice for coastal zones and damp tunnels.

Sourcing from Signum Rail Fasteners China

With advanced automated forging lines, rigorous metallurgical labs, and full compliance with UIC864-1 and ASTM A66 guidelines, Signum Rail Fasteners China is your trusted B2B partner for high-volume track component supply. Whether your project demands standard Ss8 spikes or high-tensile Ss35 anchors, our engineering team delivers precision at scale.

Frequently Asked Questions (FAQ)

What are the main differences between Ss8, Ss25, and Ss35 rail screw spikes?

While all three spikes share a standard M24 thread diameter and a 12.5 mm thread pitch, they vary in length for specific track setups:

· Ss8 (145mm/165mm) is ideal for standard timber sleepers and ribbed tie plates.

· Ss25 (185mm) is optimized for concrete sleepers with cast-in plastic dowels.

· Ss35 (215mm) features an extended length to provide maximum anchoring depth for heavy-haul tracks and sharp curves.

Do Signum's Ss series screw spikes meet international standards?

Yes. Every batch of Ss8, Ss25, and Ss35 screw spikes manufactured by Signum Rail Fasteners China complies strictly with the international UIC864-1 and ASTM A66 engineering standards, ensuring worldwide compatibility.

What is the tested pull-out resistance of these rail screw spikes?

While global rail safety standards require a minimum pull-out force of ≥ 60 kN, Signum’s premium manufacturing processes achieve factory batch test averages between 75 kN and 92 kN when anchored into high-density plastic dowels.

What steel grades are available for the Ss series?

Signum supplies these track fasteners in multiple strength profiles to fit different transit needs. We offer standard Grade 5.6 carbon steel spikes as well as high-tensile Grade 8.8 alloy steel spikes, which deliver a massive tensile strength of 800 to 1000 MPa for heavy freight corridors.

Which surface coating is best for high-humidity or coastal railway lines?

Hot-Dip Galvanization (HDG) provides the best long-term corrosion defense. Our HDG spikes receive a zinc layer thicker than 500 g/m² (70–85 μm), enabling them to withstand over 720 hours of salt spray testing without developing red rust.

Why does the roll-threaded design perform better than smooth drive spikes?

The precision roll-threaded profile of the Ss series mechanically cuts into wooden sleepers or plastic dowels. This secure interlocking mechanism distributes vertical forces evenly, minimizes longitudinal rail creep, and prevents "spike killing" (structural wood fiber rot).