Abstract: A method for conveying a working medium within a supply line (2), wherein a pig package (48) is moved into the supply line (2) by means of a pushing medium conveyed by a first pump (40) to a proximal end of the supply line (2), is intended to enable TPS operation in a manner that is as technically simple as possible. To this end, a first conveying quantity of the pushing medium is determined by means of a first flow-measuring cell (44) associated with the proximal end, wherein a position of the pig package (48) in the supply line (2) is determined from the first conveying quantity and information about the cross-section of the supply line (2).