ABSTRAKThe implementation of High Speed Railway (HSR) networks involves a large amount of financial support imposing, not only at the conception and design level, but also during the lineoperation, a demanding, a complete, and a rigorous estimation of the total cost involved in the life cycle of the system. By using appropriatetools for estimating HSR life cycle costs (LCC), itis possible to minimize the final cost and, at the same time, to identify the most important aspects and parameters influencing the cost evaluation. Research, therefore,is not only required on the LCC modeling, but also on the estimation of major degradation factors and in theassessment of its impact on the maintenance needs. This paper deals with this former aspect. The various methodologies for evaluating the geometrical track quality are presented andcompared to each other, namely the J Synthetic Coefficient, the Indian TGI and also the approach presented in the European StandardEN 13848-5. In order to compare these threemethodologies, they are applied to a railway stretch of the Portuguese Northern Railway Line. By doing so, the prediction of track degradation rate within the period of research can bedetermined, which possibly is used in the future for defining cost-effective maintenance strategies.