• Bear static and dynamic loads of car‑body and bogie frame under high‑speed operation
• Attenuate high‑frequency wheel‑rail excitation vibration, suppress hunting motion of bogies
• Transmit longitudinal, lateral and vertical forces between car‑body, bogie and axle‑box
• Realize flexible positioning with controlled allowable displacement for safe curve negotiation at high speed
• Restrict car‑body rolling movement; reduce structural‑borne noise inside vehicle compartment
• Serve as fail‑safe backup for air‑spring system; protect bogie mechanical assemblies and extend service life