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Remanufacture of rail wheels: Aurora Project


Each year, LUR produces 34,000 new wheels for the UK rail sector at a cost of over £20 million. Added to this are an estimated 200,000 rail wheels on underground networks and over 30 million wheels on overland services across Europe. With demand rising on the railways, wheel replacement is becoming increasingly costly. Currently, maintenance involves turning all of the wheels on a train to match the diameter of the most worn wheel, which is turned to stay as close as possible to the ideal profile. Where the wheel damage is too severe the wheel has to be scrapped, which can have an impact on fleet availability. As a result, TWI collaborated on the Aurora project to assess the viability of repairing worn rail wheels using cladding.

Work Programme

The project aimed to develop a remanufacturing cell for rail wheels, including in-process and post-production inspection to ensure accuracy and integrity of the wheels. Aside from the practical implications, the project also needed to address a lack of industry standards for repaired wheels due to the safety-critical nature of the work. 

TWI used submerged arc welding, as it was the only process that was able to deposit material quickly enough to maintain process pre-heat, with deposition occurring at ~12kg/hour with a maintained interpass temperature of 400°C. When tested, the deposit bead overlap factor gave a very smooth layer surface, although it was not possible to lay material onto radii on the inboard corner or flange and additional work is required to limit additional deposition to re-build an acceptable profile.

The manufacturing cell created was reconfigurable so that it could accommodate wheelsets of different diameters.  Software was written to control the automation of the welding process, while being able to sample the weld current, volts and wire feed speed, weld speed (wheel rotation speed) at pre-set intervals to give a record of the weld. 

Aurora remanufacturing cell
Aurora remanufacturing cell


The project found that a third layer of cladding on the wheel caused cracks to form during cooling at the flange. To avoid this, it was decided that welding should be done in two separate programmes – one for the tread and one for the flange – stopping and resetting between the two welds. 
The in-process inspection was found to be best using Laser Ultrasonic Techniques (LUT). LUT was able to withstand high temperatures as well as coping with wheel geometry, limited spatial access and permitted defect size, while maintaining good results.

Next Steps

While the Aurora project has proven successful, it is just the start of the journey to introduce remanufactured wheel standards to the rail industry. The additional research required includes evolving dimensions of performance alongside a wider examination of the remanufacturing solution for different rail operators across the UK and Europe.

For more information, please email

Remanufactured train wheel
Remanufactured train wheel