The Train Tunnel Escape

A hiker is walking through a straight train tunnel. She has reached exactly one-quarter of the way through the tunnel when she hears a train approaching from behind her (from the tunnel entrance). The train travels at 60 km/h. She realises that if she runs toward the train (back toward the entrance), she will just barely escape — reaching the entrance exactly as the train arrives. She also realises that if she runs in the other direction (toward the far exit), she will also just barely escape — reaching the far end exactly as the train arrives. How fast can the hiker run?