Abstract: A cleaning and obstruction locating pipeline pig according to this invention includes a magnetic nose bumper at its forward end and a disc located in the central bypass flow passageway that prevents product from flowing through the central bypass flow passageway while the pig is travelling forward in the pipeline. If debris ahead of the pig causes the pig to become stuck in the pipeline, product flow pressing upon the disc ruptures the disc, thereby allowing product to flow through the central bypass flow passageway until the pig is located and removed from the pipeline. The pig may also be used to locate a previously launched but stuck pipeline pig.