A pipeline cleaning tool is constructed with an elongated support mechanism having a rigid cutting unit mounted at one end and a folding propulsion assembly mounted at the other end. The propulsion assembly includes a system of folding sector panels that are hinged to a central hub for rotation relative thereto about tangential axes of rotation. A separate expansion flap is secured to each sector panel for rotation relative thereto about a radially oriented axis of rotation by a hinged connection to one radial side edge. Each expansion flap partially overlaps the upstream face of the sector panel immediately adjacent to that upon which it is mounted. The area of overlap is controlled by the extent to which the sector panels of the propulsion unit are folded back toward the supporting shaft. The greater the extent of folding, the greater will be the area of overlap of each expansion flap upon the upstream face of an adjacent sector panel. A disc-shaped backing seal is employed immediately adjacent the sector panels and the expansion flaps against the upstream faces thereof. A pressure differential is thereby formed across the propulsion unit which propels the cleaning tool along a section of pipeline to be cleaned. Radially projecting teeth and, in some cases, longitudinally projecting blades, slice through and break up accumulated clogging material that adheres to the inside of the pipeline wall as the pipeline cleaning unit is forced through the pipeline by pressure against the upstream side of the propulsion unit. The distance of radial projection of the teeth of the cutting unit may be made adjustable.