Pi2 pulsations have been observed to occur at low latitudes during extremely quiet conditions. We have found an excellent correlation between an occurrence of such a Pi2 train and high-latitude Pi2 pulsations and bay-like disturbances in ground magnetic field of the type associated with poleward boundary intensifications (PBIs). The Pi2s and the PBIs that are inferred to occur simultaneously, show a ~30 min repetition rate. They also exhibit an excellent correlation with energetic particle enhancements in the near Earth tail plasma sheet. These associations demonstrate the large-scale nature of the magnetosphere-ionosphere disturbance that gives rise to PBIs and shows that the disturbance may have important effects on energetic plasma sheet particles. They show for the first time that PBIs are associated with clearly observable Pi2 pulsations at low latitudes. Our observations are consistent with the possibility that PBIs are part of a large-scale magnetospheric oscillation with ~30 min period.