Less is more

FLEXX* Curve is an enhanced HALL®, resulting from a collaboration between BOMBARDIER and Trelleborg. FLEXX Curve with frequency-depending longitudinal stiffness, like the HALL®, has following advantages over conventional axle guide bushings:
  • Reduced curve squeal noise
  • Reduced wheel and track wear
  • Reduced energy consumption
  • Reduced track access charges.
In addition to the HALL®  functionalities, FLEXX Curve is able to: 
  • Adapt small curves better than HALL®  (higher longitudinal deflection capacity)
  • Allows easy hydraulic cross connection to maintain curving performance, under high traction and braking forces
  • Be loaded with high vertical forces, based on its innovative design
  • Be installed as plug-and-play solution, for BOMBARDIER* TALENT* 2 and 3, BOMBARDIER* TWINDEXX* and upcoming BOMBARDIER* FLEXX* Compact bogies.

Contact us

Ask an expert

Speak to one of our team

FLEXX® Curve types

Trelleborg FLEXX Curve


  • Plug-and-play solution
  • Traction and braking forces are mechanically compensated 
  • Cx stat.= 3 kN/mm (trailer bogie)
  • Cx stat.= 5 kN/mm (motor bogie)

Trelleborg FLEXX Curve

Cross Coupled

  • Connected FLEXX Curve units from left to right bogie side
  • Traction and braking forces are hydraulically compensated
  • Cx stat. = 2 kN/mm (all bogies)

Trelleborg FLEXX Curve

Cross Coupled/PRS

  • Cross coupled design
  • Outstanding curving performance by valve-controlled fluid flow
  • Cx stat. < 2 kN/mm (all bogies)

FLEXX® Curve characteristics

Trelleborg FLEXX Curve

Design space

Trelleborg FLEXX Curve


Trelleborg FLEXX Curve

Longitudinal Stiffness CX

Why a hydraulic axle guide element?

The conflict of aims between a good curving behavior and stable running at high speed can be solved by conventional parts only in form of a compromise. HALL® bush has the ideal characteristic for good curving behavior and stable running at high speed.

FLEXX Curve  Chart
FLEXX Curve chart

FLEXX® Compact Bogie

Building Block Primary Suspension Design Types

Trelleborg FLEXX Curve

«Conventional» Cx=25kN/mm

Trelleborg FLEXX Curve

FLEXX Curve «Standard» Cx = 3-5kN/mm

Trelleborg FLEXX Curve

FLEXX Curve «Cross-Coupled»Cx = 2kN/mm

Trelleborg FLEXX Curve

FLEXX Curve «Cross-Coupled / PRS»Cx < 2kN/mm

Speak to one of our rail and mass transit experts

Turning your challenges into new opportunities. Complete the form below and one of our experts will contact you.

What is your next challenge?

Trelleborg AVS Engineer