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The Nabla Evolution Fastening System is an improved version of the original Nabla System that has been proven throughout the world for several decades.

The original Nabla Fastening System has provided safe and reliable tracks in Tram, LRT, Metro, Main Line and High Speed tracks. The special shape of the Nabla blade generates a dynamically stable toe load on the rails when the nut is torqued.

The Nabla Evolution fastening system gives greater performance in tight radius curves, maintains consistent track gauge, increased electrical insulation and improves the overall life expectancy of the assembly components.

  • Tightening to refusal providing a constant force on the rail foot
  • Lateral adjustment in 1.25mm increment
  • Maintains efficient track gauge control and limits rail movement

The Nabla Evolution Fastening System can be used on concrete sleepers in ballast, tram systems (with or without plastic baseplate) and can also be provided for track structure interface using reduced or zero toe load.

Product features by product sector

  • Why Nabla Evolution?
  • Tram
  • LRT/Metro
  • Bridges
  • Main Line (Passenger Freight)
  • High Speed
  • The Nabla Evolution Fastening System provides greater control of track gauge and is ideal for use in tight radius curves, it has been installed in France (“Plan Rail Auvergne”) in order to sustain the track in the Massif Central.

    The system provides greater lateral adjustment than the original Nabla in increments of 1.25mm.

    After following the installation and tightening instructions there is no need for any subsequent checks on the tightness.

    Optional anchor types are available to suit customer requirements.

  • For Tram systems a Tram version of the Nabla Evolution system is available, alternatively the plastic baseplate Nabla Tram system can be used for Top Down or Bottom Up automatic construction. You can find more information about Nabla Tram here.


  • This product is suitable for use on LRT/Metro.

  • The Pandrol Nabla Evolution system is suitable on all types of ballasted bridges.

  • This product is suitable for use on Main Line (Passenger freight).

  • This product is suitable for use on High Speed.