An adhesion estimating device for a brake system of a rail vehicle having brakes (3', 3", 3"', 3"") that can individually brake wheelsets of the rail vehicle, the adhesion estimating device comprising: a braking demand distributing unit for redistributing an overall braking demand into individual braking demands to the individual brakes (3', 3", 3''', 3''''), wherein the braking demand distributing unit is configured to redistribute the overall braking demand requested for a predetermined deceleration into different individual braking demands such that the individual braking demands result in the predetermined deceleration, and an evaluation unit determining a correlation between a current adhesion value allocated to a current individual braking demand to one of the brakes (3', 3", 3''', 3"") and a current slip of a wheel of the wheelset braked by the one of the brakes (3', 3", 3''', 3''''), detected by a detection system and input into the evaluation unit, for estimating an adhesion value between the wheel and the rail, wherein it further comprises a memory area configured to store correlations between adhesion values and individual braking demands, and the adhesion estimating device is configured to receive data from a wheel slip protection system, wherein the adhesion estimating device is configured to detect an activity of the wheel slip protection system due to occurrence of the slip of at least one of the wheels caused by a current individual braking demand, and the evaluation unit is configured to estimate the adhesion value from the current individual braking demand, characterized in that the adhesion estimating device is further configured to detect the activity of the wheel slip protection system due to the occurrence of the slip of several wheels caused by current individual braking demands, and to estimate, from the current individual braking demands, a range of the adhesion value between a lower adhesion limit value allocated to a current maximum individual braking demand without causing activity of the slip protection system and an upper adhesion limit value allocated to a current minimum individual braking demand with causing activity of the slip protection system. a braking demand distributing unit for redistributing an overall braking demand into individual braking demands to the individual brakes (3', 3", 3''', 3''''), wherein the braking demand distributing unit is configured to redistribute the overall braking demand requested for a predetermined deceleration into different individual braking demands such that the individual braking demands result in the predetermined deceleration, and an evaluation unit determining a correlation between a current adhesion value allocated to a current individual braking demand to one of the brakes (3', 3", 3''', 3"") and a current slip of a wheel of the wheelset braked by the one of the brakes (3', 3", 3''', 3''''), detected by a detection system and input into the evaluation unit, for estimating an adhesion value between the wheel and the rail, wherein it further comprises a memory area configured to store correlations between adhesion values and individual braking demands, and the adhesion estimating device is configured to receive data from a wheel slip protection system, wherein the adhesion estimating device is configured to detect an activity of the wheel slip protection system due to occurrence of the slip of at least one of the wheels caused by a current individual braking demand, and the evaluation unit is configured to estimate the adhesion value from the current individual braking demand, characterized in that the adhesion estimating device is further configured to detect the activity of the wheel slip protection system due to the occurrence of the slip of several wheels caused by current individual braking demands, and to estimate, from the current individual braking demands, a range of the adhesion value between a lower adhesion limit value allocated to a current maximum individual braking demand without causing activity of the slip protection system and an upper adhesion limit value allocated to a current minimum individual braking demand with causing activity of the slip protection system.