Blocking at self loading wagons happens if the torque at the power take-off extends a certain level. It results in a compulsory stop due to a cut in the transmission of torque. By a virtual sensor, accessing information of a swath scanner mounted at the front of the tractor, a prediction of the future power take-off torque can be done. This work presents possibilities how to set up the model for this sensor and to use the sensor information for blocking intervention like decreasing the vehicle speed.