A new way to repair damaged rails using a laser has proven its applicability on real models. But neutrons also came in handy.

A group of engineers and analysts from several technical universities have developed a reliable and efficient laser technology for rail repair using neutron scattering. This method can increase the service life and reduce the cost of maintaining the railways.

They turned to laser cladding, a technology that uses a laser to apply the desired material, such as metals, to surfaces. In an experiment, engineers coated a damaged rail with one to two layers of stainless steel or cobalt-based alloy using a laser.

It turned out that the metals deposited by the laser reliably cover and fill the damage in the rails, however, residual stresses appear during the deposition process. And that could be a problem. Therefore, the team developed a new approach to estimating residual stresses on a real-sized model of a plated rail.

“Only neutrons can penetrate the material of which the rail is made and measure the stress distribution in a non-destructive manner,” the authors of the experiment note. “This is how we found that post-coating heat treatment significantly reduces residual stresses both on the rail surface and underneath it.”

Apparently, this method is better than the now popular arc welding technology, which is more than 110 years old. In the future, laser technology can be turned into a portable and mobile way of repairing railways, which will be especially useful in remote areas.