Bearings are one of the most important components in a railway vehicle for safety, since a failsafe design is not available. Contact fatigue, internal clearance, corrosion, and contamination of the lubricating oil can cause bearing failures. Generally, failures show up as imperfections in the ball race, in the ball/roller or in the retainer. The more frequent defects are caused by contact fatigue [1]. The analytical methodology (Methodology I) is an alternative approach proposed by the authors [1], inspired by a procedure used to design rail shafts [2]. The purpose is to compare the obtained life using methodology I, with the life estimated by LKAB company. The latter uses a calculation method well-established in manuals of bearing manufacturers such as SKF and Timken. This is to avoid a drawback observed in this type of approach, namely, the lack of rigour in defining terms associated with the mathematical model used to estimate L10. The research goal is to perform an inspection and analysis of the functioning of the bearings most commonly used on railways in order to estimate the bearings' life under real operating conditions.