A system for storing pigs (22) and launching them into a pipeline comprises a pig storage barrel (20) having an inlet end (21) and an outlet end and an inside diameter sized to accommodate the pigs (22), the storage barrel (20) including a pig parking chamber (40) for controlling release of the pigs, and a pig launching chamber (60) downstream of the storage barrel. The launching chamber (60) is connected to the pipeline (102) so as to be able to launch a pig into the pipeline (102). The apparatus also includes a hydraulic pig advancing system in fluid communication with the storage barrel (20) and the launching chamber (60) and a fluid flush system in fluid communication with the storage barrel chamber and the launching chamber. The method includes flushing the storage barrel and the launching chamber after each launching cycle so that between launchings the system is filled with hydraulic fluid.