http://www.metro.co.uk/weird/article...0&in_page_id=2

ISTR an episode of "Mythbusters" that suggested this wasn't possible
(the stream would probably stops being a continuous one by the time it
hit the live rail and thus wouldn't be able to conduct), although
given the reports say he "walked onto the track" perhaps he
accidentally made contact with the electrified line another way.

~cj