A method of detecting rubs during operation of a turbomachine comprising at least one rotating object having a tip and a shelf is provided. The method includes generating signals representative of a sensed parameter and processing the signals to generate height versus time data for the tip. The height of the tip corresponds to the distance between the tip and the shelf. The method further includes monitoring the height versus time data, in order to determine whether a change in the height data exceeds a threshold value, and detecting a rub of the rotating object(s) on a second object, when the change in the height data exceeds the threshold value. A rub detection system for a turbomachine and a turbine engine system with rub detection are also provided.