Tuesday, June 23, 2015

overhead electric wires and live third rail electrification illustrations, circa 1937


The Southern Railway of England was notable for extending live third rails beyond the London metropolitan area, unlike the usual practice of installing overhead wires.  When low voltage DC is involved with high currents, thick conductors like steel rails make more sense as resistance is much reduced.  With high voltage AC systems and low currents it ceases to be an issue.  There is also the obvious safety hazard with third rails.

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