Abstract: Apparatus for forming and installing underground drainpipe in subterranean passages. The pipe is formed from a web of porous or non-porous sheet plastic which is drawn from a dispensing roll through curling and shaping devices protected by a transparent shield to provide a tube, these devices being mounted on a frame positionable in a trench or other depression in the soil. The end of the tube is attached to a mole at the end of a power driven blade, with the mole forming an underground passage for the following tube. Tensioning and positioning rollers are carried on the frame to feed the web to the tube forming devices at a predetermined angle and tension. A pressor roller and its support bracket interengage complimentary tongues and slots formed along the edges of the web for holding the web in its tubular form.