Nabla Spring Blade For Fasteners System

The Nabla Spring Blade (also known as the Nabla clip or Nabla plate) is a critical elastic component of the Nabla rail fastening system. It is widely recognized for its use on French TGV high-speed lines and across rail networks in Europe and Africa. 

Key Technical Features

• Design: It features a unique trapezoidal, shovel-like shape with a central hole for a bolted fastening. This shape generates a dynamically stable toe load when the rail nut is torqued.

• Material: High-strength alloy spring steel, such as 60Si2MnA or 60Si2CrA, with a hardness range of 42–55 HRC.

• Performance:  (Toe Load: 11 kN;Static Stiffness: 70 kN/mm;Adjustment: From -8 to +4 mm and lateral fine-tuning in 1.25 mm increments (up to ±7.5 mm per rail seat);Durability: Over 3 million cycles without breaking. )

System Components

The Nabla fastening system typically includes:

• Nabla Spring Blade: The main elastic clamping element.

• Insulator: Specially designed glass-reinforced material for electrical insulation and lateral force absorption.

• High-Strength Bolt/Screw Spike: Secures the assembly to the sleeper (concrete or wooden).

• Spring Washer: Used with the bolt to maintain tension. 

Applications

The system is suitable for all track types, including high-speed rail, metros, trams, and heavy haul tracks. It is particularly effective for tracks with tight radius curves due to its ability to maintain precise track gauge and absorb lateral forces.