Most electrified railway in Europe operates at 15 kV 16.7 Hz AC or 25 kV 50 Hz AC.

Power is typically produced between about 2.3 kV and 30 kV and stepped up to 115 kV to 765 kV AC for long distance transmission (Wikipedia).

If the railway overhead wires were fed by a single power source how far from this source could the rail network extend?
Is there a limit to the number of users that could connect to the railway overhead wires?

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    $\begingroup$ The one safety issue I have with such an idea is the cable is closer to the ground than is usual for high voltage power lines making it easier to people to be in contact with them. $\endgroup$ – Fred Dec 5 '20 at 11:06
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    $\begingroup$ Who owns them, what happens when they need maintenace from the railway use and homes then get cut off? Or will you have multiple supplies to everywhere? $\endgroup$ – Solar Mike Dec 5 '20 at 11:10
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    $\begingroup$ What happens when everybody turns on their electric oven and the trains slow down? $\endgroup$ – Michael Harvey Dec 6 '20 at 11:05
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    $\begingroup$ 25 kV railways are supplied from the grid anyhow. The feeder stations are spaced maybe 60 km apart. The lines over the tracks carry a single phase, they are sectioned to even the overall load across 3 phases, with insulating spacers in the wire, they are sized for the maximum traction load (5 - 10 MW trains). If the wires were fatter the supporting structures would be more tricky to design, and who would pay for that? The trains have motor control by tap changer, thyristor, IGBT, etc, which means dirty power to houses connected. Industrial users would want 3 phase. $\endgroup$ – Michael Harvey Dec 6 '20 at 11:36
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    $\begingroup$ @Fred - the traction supply wires are directly over the tracks on which the trains run, which is already an unhealthy place for the general public to be, and trespassing on the railway is a criminal offence in many countries. $\endgroup$ – Michael Harvey Dec 6 '20 at 11:55

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