A reconnection system for reconnecting electrically powered train units to electrical power supply lines which extend along respective tracks of a rail network, the network being divided into plural power supply sections (A-D) with each power supply section having a respective source of electrical power for the supply lines of the tracks in that section, the reconnection system including: plural of the train units, each unit having a measuring device to detect failure and recovery of power supply by the supply line of the track on which the unit is currently located, a breaker to disconnect and reconnect traction equipment of the unit with the supply line, and a supervision system which is operably connected to the measuring device and the breaker; the reconnection system characterized by: a delay generating system which is configured to extemporaneously determine a respective and different breaker closing time for each of the train units within a given power supply section on recovery of the power supply to the train units, and to provide the supervision systems of the train units with the respective breaker closing times thus-determined; wherein each supervision system is programed to: command its breaker to disconnect its traction equipment when its measuring device detects failure of the power supply; and after detection by the measuring device of recovery of the power supply, command the breaker to reconnect the traction equipment according to the breaker closing time for its train unit provided by the delay generating system; whereby a breaker closing time delay at which any given one of the breakers is commanded to reconnect its traction equipment varies as between disconnection and reconnection events. a delay generating system which is configured to extemporaneously determine a respective and different breaker closing time for each of the train units within a given power supply section on recovery of the power supply to the train units, and to provide the supervision systems of the train units with the respective breaker closing times thus-determined; wherein each supervision system is programed to: command its breaker to disconnect its traction equipment when its measuring device detects failure of the power supply; and after detection by the measuring device of recovery of the power supply, command the breaker to reconnect the traction equipment according to the breaker closing time for its train unit provided by the delay generating system; whereby a breaker closing time delay at which any given one of the breakers is commanded to reconnect its traction equipment varies as between disconnection and reconnection events. command its breaker to disconnect its traction equipment when its measuring device detects failure of the power supply; and after detection by the measuring device of recovery of the power supply, command the breaker to reconnect the traction equipment according to the breaker closing time for its train unit provided by the delay generating system; whereby a breaker closing time delay at which any given one of the breakers is commanded to reconnect its traction equipment varies as between disconnection and reconnection events.