Nabla Clips S1 C1 N1

Nabla Clips (specifically models S1, C1, and N1) are specialized elastic rail fastening components primarily used to secure steel rails to concrete or wooden sleepers in railway infrastructure. Developed by Pandrol, these clips are widely utilized in France, Japan, and parts of Africa for tramways, light rail (LRT), and high-speed rail tracks. 

Key Models and Specifications

The primary difference between these models often relates to their mechanical strength and the specific track environment they are designed for:

• Nabla C1: A standard flat steel clip compliant with NF F 50-015 standards. It is typically part of a system that includes a rail insulator, screw spikes (such as Tr 22x160), and flat washers.

• Nabla S1: A heavy-duty variant designed for specific industrial or standard track applications.

• Nabla N1: Often used in systems requiring specific lateral force absorption and elasticity to maintain track gauge in tight curves. 

Core Functions

• Elasticity & Clamping Force: The unique blade shape generates a dynamically stable toe load when tightened, preventing rail roll and maintaining track gauge.

• Lateral Force Absorption: Constructed from spring steel or glass-reinforced materials to withstand heavy pressure in tight radius curves.

• Noise and Vibration Reduction: Helps dampen environmental impact, making them ideal for urban tram systems.

• Electrical Insulation: Often paired with plastic-encased baseplates or specialized insulators to provide high levels of electrical isolation. 

Typical System Components

A complete Nabla fastening assembly generally includes: 

• Nabla Clip (S1, C1, or N1): The main elastic component.

• Screw Spike/T-Bolt: Typically a Tr22 type for concrete sleepers.

• Rail Pad: Provides cushioning between the rail and sleeper, with stiffness options ranging from 35 MN/m (tram) to 400+ MN/m (heavy haul).

• Insulator: Used for lateral adjustment and electrical protection.