NABLA CLIP G4 | Direct Manufacturer

The Nabla clip G4 is a specialized flat steel elastic rail clip manufactured by Pandrol (Ref: FGA0004). It is a core component of the Nabla fastening system, widely recognized for its use in European (particularly French) and African rail networks for tramways, metros, and high-speed lines. 

Technical Specifications

The G4 clip is engineered for high performance in demanding environments, specifically compliant with the NF F 50-015 standard. 

• Material: Manufactured from high-grade alloy spring steel, typically 60Si2MnA or 60Si2CrA.

• Dimensions: Usually available in thicknesses of 4mm or 4.5mm.

• Performance: Capable of sustaining over 3 million cycles (some variants up to 5 million) without breaking.

• Clamping Force: Provides a dynamically stable toe load exceeding 16 kN when properly torqued.

• Hardness: Heat-treated to a range of 42-48 HRC for optimal elasticity and durability. 

System Components

A standard Nabla G4 assembly on a sleeper typically requires four of each of the following: 

• Nabla Clip (G4): The elastic element providing clamping force.

• Insulator (Guide Plate): Made of glass-reinforced Nylon 66 (PA66) to provide electrical insulation and lateral force absorption.

• Screw Spike: A high-strength anchor (Grade 5.6) used to secure the assembly to concrete or wood sleepers.

• Spring Washer: Used under the nut to maintain tension.

• Rail Pad: Placed under the rail foot to reduce vibration and protect the sleeper. 

Installation & Maintenance

The system is designed for "tightening by contact," meaning the anchor screw is tightened until it makes contact with the clip, ensuring consistent application of force. 

• Torque Range: Typically requires a tightening torque between 250 and 400 Nm.

• Adjustability: The insulators allow for fine gauge tuning in 1.25mm increments, providing a total lateral adjustment of up to ±7.5mm per rail seat.

• Maintenance: Its deep-post insulator design offers high resistance to wear, making it a low-maintenance solution for high-speed and urban transit systems.