Fully biodegradable, solid-free, long-term lubricating grease of NLGI class 1 for the lubrication of track side face/wheel flange as well as the wheel steering system in bogies. The biodegradable ester oil based lubricant has high adhesive strength, outstanding high load carrying capacity and excellent oxidation stability. It is resistant to water/salt water, reduces significantly wear and shows good temperature behaviour during all seasons.