seismometers installed along the coast and near the tracks. Senses the earthquake and trains respond if necessary. I believe if the epicenter of the quake occur

seismometers installed along the coast and near the tracks. Senses the earthquake and trains respond if necessary. I believe if the epicenter of the quake occurred directly under a moving train this system would fail(or too close react). However, that appears never to have happened and is probably extremely unlikely.