Railway Anchor Bolt

Anchor bolts are installed in pre-drilled holes in the sleepers. Through high-strength threads, spring washers, flat washers, and lock nuts, they lock the rail clip to the sleeper, bearing the 100–150 kN longitudinal shear force generated when a single-axle 25–30 t freight car brakes. Unlike turnout bolts, their design life is required to be 30 years maintenance-free, directly affecting track smoothness and train safety.

 

 

 

Performance Parameter	Common Carbon Steel Material	High-Strength Alloy Steel Material
Tensile Strength	About 400MPa – 600MPa	800MPa – 1200MPa or even higher
Yield Strength	200MPa – 300MPa	400MPa – 600MPa
Shear Strength	Approximately 0.5 – 0.6 times the tensile strength	Approximately 0.5 – 0.6 times the tensile strength
Fatigue Strength	The strength index that the bolt can withstand the maximum stress without fatigue failure under alternating loads. The specific value varies depending on materials, processes, and load conditions	The strength index that the bolt can withstand the maximum stress without fatigue failure under alternating loads. The specific value varies depending on materials, processes, and load conditions

 

 

Double anti-loosening protection: The head has 30° anti-loosening teeth on the bottom surface, which, when used with a nylon insert lock nut, provides an anti-loosening torque of >600 N·m.

Eccentricity compensation: The T-head design allows for a 1:20 taper to accommodate deviations in the inclination angle of the sleeper mounting hole.

Interference anchoring: The interference between the smooth rod section and the concrete hole is 0.08–0.12 mm, which, when used with chemical anchoring adhesive or expansion sleeves, provides a pull-out resistance of up to 80 kN.

Identification and traceability: The head is laser-engraved with the manufacturer's mark + batch number + year, supporting full lifecycle traceability.

Corrosion protection upgrade: The zinc-aluminum-magnesium coating has a self-healing cut, extending salt spray life from 25 years to 35 years.

 

 

 

1. L-Shaped Anchoring Bolt

Details	Description
Use	Suitable for the fixation of sleepers and roadbeds, commonly found in ordinary railways or turnout areas
Material	Q235 carbon steel/45# steel/stainless steel 304
Diameter Range	M16 – M30
Length Range	200mm – 500mm
Bending Angle	90° (L – shaped)
Tensile Strength	≥500MPa
Surface Treatment	Hot – dip galvanizing/Dacromet coating

 

2. J – Shaped Anchoring Bolt

Details	Description
Use	Mostly used for track fixation in curved sections or complex terrains, with strong lateral force resistance
Material	40Cr alloy steel/stainless steel 316
Diameter Range	M20 – M36
Length Range	300mm – 600mm
Bending Arc	Semicircular (J – shaped hook head)
Tensile Strength	≥600MPa
Surface Treatment	Zinc infiltration/Epoxy resin spraying

 

3. U-Shaped Anchoring Bolt

Details	Description
Use	Used for the two-way locking of steel rails and sleepers, commonly found in high-speed railways or heavy–haul railways
Material	35CrMo alloy steel
Diameter Range	M24 – M42
Opening Width	50 mm – 120mm
Shear Strength	≥700 MPa
Surface Treatment	Hot – sprayed zinc/Phosphating treatment

 

4. T-Shaped Anchoring Bolt

Details	Description
Use	Suitable for embedded fixation in ballasted tracks or ballastless tracks
Material	Q345B low – alloy steel
Diameter Range	M18 – M32
Head Size	T – shaped head width 40mm – 80mm
Vibration Resistance Performance	Complies with TB/T 2344 standard
Surface Treatment	Electro – galvanizing/Fluorocarbon coating

 

5. Straight – Rod Anchoring Bolt (Expansion Type)

Details	Description
Use	Used for the rapid anchoring of concrete sleepers or bridge tracks
Material	20MnTiB alloy steel
Diameter Range	M12–M24
Length Range	150 mm – 400mm
Expansion Sleeve Material	Nylon/Stainless steel
Installation Torque	100 N·m – 300 N·m

 

Railway Anchor Bolts are anti-creep anchors for rails. Their interference fit, anti-loosening teeth, and high shear resistance design ensure that the rail remains firmly in place even after millions of braking impacts. Choosing the wrong bolt can lead to geometric deformation of the rail; choosing the right product can ensure 30 years of maintenance-free operation, guaranteeing the safe operation of a multi-billion dollar railway network.

 

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