Abstract: An in-line pig launching device includes a pair of guide rails on which a pig is stored before launching, a drive system for moving the pig along the guide rails and a drop tube at an end of the guide rails for accommodating the pig just before launching. The drop tube includes a guide rail extension that holds the pig in a proper orientation, against tipping, within the drop tube. The guide rail extension is linked to the drive system, such that only when the drive system moves to move a next pig will the guide rail extension release the pig from the drop tube.