A novel laboratory test rig for probing the sensitivity of rail steels to RCF and wear – first experimental results

• A novel type of laboratory twin disc test rig is presented.
• The inverted twin disc machine is able to create spin creepage.
• The testing configuration led to a huge increase of the size of the contact patch.
• Rolling contact fatigue cracks (headcheck like cracks) were generated successfully.

Increased traffic and intensified operating conditions cause more and more damage on rails manifesting themselves in rolling contact fatigue cracks and wear. Rolling contact fatigue, e.g. head checking, is classified safety critical as these cracks may lead to the derailment of a vehicle. For that reason research and development is mainly focused on designing novel, more damage resistant rail steels whereas part of the research is concentrated on testing their sensitivity to head checking. In this study a new type of laboratory test rig is presented which is capable of generating head check like rolling contact fatigue cracks under realistic contact and loading conditions. The main idea behind the design is that the contact patch size is significantly increased in a convex–concave contact configuration, realized in this special case by a shaft running inside a ring.