Railcar or Rolling stock that is referring to all vehicles moving on railway, is one of the most important component of the rail transport system. In-operation failures of the railcar results delays in transportation and therefore predicting the remaining useful life (RUL) and accordingly considering the preventive maintenance activities are essential. The RUL estimation is a key factor in predictive maintenance that has an influence on the maintenance scheduling, spare parts prediction and also the operational performance of the assets. This paper aims to model and analyze the RUL of railcars at LKAB, a Swedish Mining Company. To achieve this goal, first the failure behavior of the critical subsystems was analyzed and discussed. Then, with considering the effective operational factors (covariates), proportional hazard model (PHM) is applied to calculate the reliability functions. In this concept, RUL of the railcars can be obtained and discussed at the various initial survival times.