Track Bolt w/Nut & Lock Washer

Looking for reliable railway track bolt, nut, and lock washer assemblies? Learn about AREMA standards, correct assembly order, and standard sizes for freight rail.

Ultimate Guide to Railway Track Bolt, Nut, and Lock Washer Assemblies

A railway track bolt with nut and lock washer is the standard, three-part heavy fastening assembly used to connect rail sections at mechanical joint bars (also known as fishplates).

Because modern railways are subject to intense, continuous dynamic loads and high vibration, the configuration and assembly order of these three parts must strictly follow AREMA (American Railway Engineering and Maintenance-of-Way Association) standards to prevent premature loosening and joint failure.

Component Breakdown: Track Bolt, Nut, and Lock Washer

To ensure maximum joint stability, each component in the assembly serves a specific engineering purpose:

1. The Railway Track Bolt

Typically features a Button Head Oval Neck (BHON) design. The specialized oval neck locks tightly into place inside the joint bar hole. This design eliminates bolt rotation during installation, allowing maintenance crews to tighten the assembly using a single wrench.

2. The Heavy Square Nut

Usually a Heavy Square Nut or heavy hex nut manufactured from heat-treated carbon steel. The extra thickness and robust profile of a heavy square nut ensure maximum thread engagement and proof load capability under extreme tension.

3. The Lock Washer

An AREMA spring washer utilizing a split-ring design. This critical component maintains structural tension, preventing displacement and thread back-off which can cause severe, dangerous vibration along the track line.

Correct Assembly Order for Track Bolts

When installing railway fasteners, components must be stacked in a precise sequence to ensure the mechanical locking mechanism functions properly:

1. Insert the Bolt: Pass the BHON track bolt completely through the joint bar and the rail web.

2. Apply the Lock Washer: Slide the split spring washer over the exposed threads, seating it directly against the outer joint bar surface.

3. Thread the Nut: Thread and tighten the heavy square nut down firmly over the lock washer.

How it works: The split lock washer works by biting into both the face of the nut and the joint bar. This action creates constant spring tension that resists friction loss and absorbs ongoing track vibrations.

Track Bolt, Nut, and Lock Washer Sizes and Specifications

In North American freight, transit, and industrial rail networks, these assemblies are commonly sold pre-packaged in heavy steel kegs or plastic pails. Standard heavy-duty sizes include:

· 1" x 6" Assemblies: The standard size mandated for 115RE and 119RE rail sections.

· 1" x 5-1/2" Assemblies: Frequently utilized for older or lighter 100-lb AREMA rail profiles.

· 1-1/8" x 6-1/2" Assemblies: Heavy-duty kits manufactured specifically for 132RE, 136RE, and 141RE heavy freight corridors.

Custom Railway Fastener Manufacturing by Signum Rail

Signum Rail Fasteners China manufactures premium railway track bolts with heavy square nuts according to our clients’ exact technical drawings and specifications.

As a trusted global supplier, our railway track bolts and square nuts are regularly exported to transit authorities and contractors across Europe, North America, and worldwide. Backed by a strict internal quality control team and excellent after-sales service, Signum Rail products deliver the durability needed for demanding rail infrastructure.

Contact Signum Rail Today for a Custom Project Quote.