Plain oiled,hot dip galvanized,zinc plated Ss8 Sleeper Screw Spike
Oct 21, 2025
What is an Ss8 sleeper screw spike?
Railway screw spikes are threaded fasteners used to fix the rail foot to the sleeper. They are driven into wooden sleepers directly, or screwed into plastic ferrules cast into concrete sleepers. The Ss series is a widely used family of sleeper screws, and Ss8 is one of the most frequently specified types. Thread profiles, lengths, diameters and drive head shapes can vary according to the track standard and the sleeper system used.
Common Ss and V series dimensions
| Type | Note |
|---|---|
| Ss5-150 | Ss series, 150 mm length class |
| Ss8-140 | Ss8 type, 140 mm |
| Ss8-150 | Ss8 type, 150 mm |
| Ss8-160 | Ss8 type, 160 mm |
| Ss23-160 | Ss23 type, 160 mm |
| Ss25-165 | Ss25 type, 165 mm |
| Ss35-161 | Ss35 type, 161 mm |
| V20-135 / V23-115 / V23-135 / V23-155 / V23-215 / V26-115 | V series alternative profiles |
Types other than those listed can be produced from customer drawings.
Property classes and mechanical properties
Sleeper screws are supplied in property classes 4.6, 5.6, 8.8 and 10.9, matching the mechanical grades defined in ISO 898-1:
| Grade | Material | Tensile (MPa) | Yield (MPa) | Elongation | Cold bending |
|---|---|---|---|---|---|
| 4.6 | Q235 | 400 min | 240 min | 22% min | 90 deg without crack |
| 5.6 | 35# | 500 min | 300 min | 20% min | 90 deg without crack |
| 8.8 | 45# | 800 min | 640 min | 12% min | 90 deg without crack |
| 10.9 | 40Cr | 1000 min | 900 min | 9% min | 90 deg without crack |
Surface finishes
The Ss8 screw spike can be supplied plain (oiled), oxide black, zinc plated, hot-dip galvanized, waxed, bitumen coated, Dacromet or sherardized. Plain and oiled finishes keep the original steel color and suit general conditions; hot-dip galvanizing provides a thick zinc layer for coastal and humid environments; zinc plating gives an economical protective layer where corrosion risk is moderate.
Why the thread matters
The threaded design provides higher clamping force and pull-out resistance than a plain dog spike. It resists longitudinal and lateral vibration generated during train operation, which is why screw spikes are standard on high-speed, heavy-haul and urban transit lines where fastening security is critical.
Standards and Compliance
Ss series sleeper screws are manufactured with reference to ISO 898-1 for mechanical properties, UIC 864-1 for track screw dimensions and NF F 50-500 for French rail fastening requirements.
FAQ
What do the numbers in Ss8-150 mean?
The type code identifies the Ss series and the nominal length in millimeters; Ss8-150 is an Ss8 screw spike with a 150 mm length class.
Can screw spikes be used on concrete sleepers?
Yes, with plastic ferrules or dowels cast into the concrete sleeper, which also provide electrical insulation.
Which grade should be chosen for heavy-haul lines?
Grade 8.8 or 10.9 with a minimum tensile strength of 800 or 1000 MPa is preferred where axle loads and vibration are severe.
What is the difference between hot-dip galvanized and zinc plated?
Hot-dip galvanizing applies a thicker zinc layer by immersion and suits coastal or corrosive sites; zinc plating is thinner and used for moderate conditions.
Which standards apply to Ss8 sleeper screws?
ISO 898-1, UIC 864-1 and NF F 50-500 are the reference standards for mechanical properties, dimensions and track application.
