Lifetime extension of rail track via laser cladding technology

The lifetime of any rail track section is limited by the issues of surface wear and rolling contact fatigue (RCF). These result from the successive interactions between train wheels and the rail head, which cause cumulative damage to the rail head surface. This leads to crack initiation and growth via RCF, which can ultimately lead to rail failure. Crack growth is currently mitigated by periodic grinding of the rail head which, although effective, also significantly shortens the life of the rail. Although more wear and RCF resistant materials are available, it would be difficult or prohibitively expensive to produce entire rail sections from them. The proposed project uses laser cladding to selectively deposit higher performance materials selectively on to the surface of standard grade rail steel, offering the possibility of tailoring the rail head surface to improve wear/RCF resistance. This technology may also be able to repair rail defects and to refurbish removed worn rails for re-introduction back into service.