In electrodynamic suspension (EDS), both the guideway and the train exert a magnetic field, and the train is levitated by the repulsive and attractive force between these magnetic fields.  In some configurations, the train can be levitated only by repulsive force. In the early stages of maglev development at the Miyazaki test track, a purely repulsive system was used instead of the later repulsive and attractive EDS system.  The magnetic field is produced either by superconducting magnets (as in JR–Maglev) or by an array of permanent magnets (as in Inductrack ). The repulsive and attractive force in the track is created by an induced magnetic field in wires or other conducting strips in the track. A major advantage of EDS maglev systems is that they are dynamically stable – changes in distance between the track and the magnets creates strong forces to return the system to its original position.  In addition, the attractive force varies in the opposite manner, providing the same adjustment effects. No active feedback control is needed.
The debate over signaling and train control between the railroads and the ICC had never really been settled, just deferred as passenger deaths declined, in part due to more travelers using their automobiles for shorter commutes and an expanding and improving highway network. It ended in 1946, when one express passenger train crashed into another one that had stopped , both operated by the Chicago, Burlington & Quincy , in Naperville, Illinois . The conductor of the first train had had it stopped in the town outside Chicago because he thought something was dragging; within two minutes it was struck from behind by another traveling at 86 miles per hour (138 km/h), killing 45. 
In early afternoon, four armed men hijack a subway train in Manhattan. They stop on a slight incline, decoupling the first car to let the rest of the train coast back. Their leader is Ryder; he connects by phone with Walter Garber, the dispatcher watching that line. Garber is a supervisor temporarily demoted while being investigated for bribery. Ryder demands $10 million within an hour, or he'll start shooting hostages. He'll deal only with Garber. The mayor okays the payoff, the news of the hostage situation sends the stock market tumbling, and it's unclear what Ryder really wants or if Garber is part of the deal. Will hostages, kidnappers, and negotiators live through this? Written by <jhailey@>