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  2. Ball lightning - Wikipedia

    en.wikipedia.org/wiki/Ball_lightning

    Ball lightning is a possible source of legends that describe luminous balls, such as the mythological Anchimayen from Argentinean and Chilean Mapuche culture.. According to a statistical investigation carried out in 1960, of 1,962 Oak Ridge National Laboratory monthly role personnel, and of all 15,923 Union Carbide Nuclear Company personnel in Oak Ridge, found 5.6% and 3.1% respectively ...

  3. North American railroad signals - Wikipedia

    en.wikipedia.org/wiki/North_American_railroad...

    The first signals employed on an American railroad were a system of flags used on the Newcastle and Frenchtown Turnpike and Rail Road in the 1830s. The railroad then developed a more effective system consisting of wooden balls, painted red, white or black, and hoisted up or down a pole on a rope-and-pulley system.

  4. Track circuit - Wikipedia

    en.wikipedia.org/wiki/Track_circuit

    Schematic drawing of track circuit for unoccupied block (series resistor next to battery not shown) Schematic drawing of occupied track circuit (series resistor next to battery not shown) A track circuit typically has power applied to each rail and a relay coil wired across them. When no train is present, the relay is energised by the current ...

  5. Track geometry - Wikipedia

    en.wikipedia.org/wiki/Track_geometry

    Crosslevel (or 'cross level') is the measurement of the difference in elevation (height) between the top surface of the two rails at any point of railroad track. The two points (each at the head of each rail) are measured at by the right angles to the reference rail. Since the rail can slightly move up and down, the measurement should be done ...

  6. North American railroad signaling - Wikipedia

    en.wikipedia.org/wiki/North_American_railroad...

    The "superior" train has right-of-track over the "inferior" trains. To move the "inferior" train against a "superior" train, train orders are used to govern the movement. On this railroad, a compilation of train rules such as superiority, and block rules such as a "clear-block" is used to proceed on the main track. Centralized Traffic Control (CTC)

  7. Top 3 lightning videos of 2024 - AOL

    www.aol.com/weather/top-3-lightning-videos-2024...

    The top spot goes to an astonishing video that dispels the common myth that lightning never strikes the same place twice. In reality, the Willis Tower in Chicago is the most frequently struck U.S ...

  8. Level crossing signals - Wikipedia

    en.wikipedia.org/wiki/Level_crossing_signals

    The time interval may be controlled by a level crossing predictor, an electronic device which is connected to the rails of a railroad track, and activates the crossing's warning devices (lights, bells, gates, etc.) at a consistent interval prior to the arrival of a train at a level crossing. [1]

  9. In 2013, Usain Bolt had the world at his feet.