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Instrumented Wheelset Technology - IWT4

A smart way of measuring wheel-rail forces

Instrumented wheelsets technology - IWT4

Instrumented wheelsets are railway wheelsets that have been instrumented and calibrated for accurately measuring the dynamic contact forces between the wheel and the rail. In the USA, Europa, China and Japan, standards for vehicles acceptance testing such as EN 14363 required instrumented wheelsets as part of the approval process for new or significantly modified vehicles. The world’s first instrumented wheelsets were produced in Sweden in the 1950’s and IWT4 can trace its heritage back to these roots.

IWT4 utilises the client’s (Vehicle manufacturers are typical clients) original wheelsets fitted to the vehicle, without any structural modification to the wheelset. No special ‘test wheels’ are required. This simplifies project logistics, reduces the delivery time, and lowers the cost of the total measurement system.  Only one side of the wheel needs to be instrumented. This simplifies the instrumentation process and enables the system to be adapted to fit challenging bogie designs

An advanced telemetry system removes the need for slip ring devices. This decreases costs, increases reliability, and simplifies installation of the system.  No destructive machining of the wheelset is required, so the structural integrity of the wheelset is preserved. This reduces risk and removes the need for additional periodic ultrasonic inspections.  Power is delivered to the system using an inductive transmission system, so as long as the vehicle is powered up, so are the IWT4s

The IWT4 technology has been used by clients around the globe since 2007.  With over 60 wheelsets produced to date, while it is a ground-breaking product, it’s also robust and field hardened.

Our IWT4 Technology services at a glance

  • For measuring wheel rail forces as part of the vehicle approval process (as per EN14363 or CFR49)
  • Either supply and commissioning of the IWT4 technology only or a turn key solution where wheelsets and full vehicle dynamics testing is undertaken.
  • Measuring the friction levels between wheel and rail
  • Measuring at high frequencies the technology can locate both singular and periodical irregularities such as corrugations, poor joints and worn switches or crossings

Click to download our IWT4 brochure


Your benefits at a glance

  • Manage your project efficiently – with an independent expert partner whom you can rely on to navigate through your projects. Our support throughout the entire project enables you to remain focussed on your core business.
  • Save time and money – with our experts working in partnership with your development, technical or commercial project management team, we are able to manage your projects successfully in terms of time, costs and quality.
  • Minimise risk – we have experience in setting up continuous risk monitoring and tool-supported risk management to avoid delays and rework.


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Middle East and Africa