Bogies are complex railway vehicle subsystems, containing brake systems, drive systems, wheelset subsystems and bogie frames with a secondary spring system. Although different bogie designs are applied for different purposes, these serve the same function. This includes supporting the rail vehicle body, helping to ensure stability on track and providing ride comfort. Directly connected to the wheelset and bogie frame is the axlebox, containing the axlebox bearing system, which is connected to further subsystems and components.Depending on railway gauge, wheel diameter and axleload, wheelsets can have different arrangements and designs. As all of these systems are critical for railway vehicle performance and reliability, careful consideration during the selection of a solution is critical.