The railway infrastructure is an extensive transport system in every country. Its parts and principles of operation are complex and varied and therefore it is not easy to establish a proper maintenance system strategy. Throughout the system, the railway track is the focal point of the infrastructure – the part in direct contact with rolling stock, which must provide a stable and safe system for movement and other railway operations. After the construction has been put into operation, the railway infrastructure manager performs diagnostic activities at a prescribed interval. They include collecting, evaluating and comparing data of construction state and its development. The aim is to identify and predict the degradation quality of the construction and to establish a quality rehabilitation strategy to bring it closer to the quality at the start of the service lifecycle. The paper deals with the theory and results of practical methods of diagnostics of the railway track quality in the Slovak Republic. It also identifies the conditions for the creation of predictive models of quality degradation from the diagnostics data and their influence on the determination of the construction maintenance strategy.

track geometry, diagnostics, quality, predictive models, rehabilitation