The traveling compression regions (TCRs) have been identified in the mid-tail with Geotail magnetic field and plasma data, and the timing of these events relative to substorm onset signatures at Los Alamos geosynchronous spacecraft has been examined. Results suggest that the near-Earth neutral line forms before geosynchronous dispersionless injection. The implications of this temporal relation for magnetospheric substorm models are discussed. (C) 2000 COSPAR. Published by Elsevier Science Ltd.