The power system of the Long Island Railroad consists of three- phase alternating current transmission at 11,000 volts, 25 cycles. Rotary converter substations convert this A.C. power to 700 volt DC third rail power at. 13,000 amps. Because extremely high voltages exist in sub-stations, no entry should be made into the area.
A friend of mine was a big shot electrical engineer and programmer for the Long Island Railroad. He said a big problem that they have is disconnecting that DC when trains are running. He said the arcing wouldn't quit and would melt the contacts, so they use hydraulic pressure to open the contacts and force dielectric oil between them to extinguish the arc.
That is some serious electricity!