nitpicker330 - You'd have to be completely out of luck to land exactly on a railway track, the odds would be very low indeed.
Powerlines do pose a bigger threat, because there's a lot more of them than railway tracks.
One of the advantages of HT lines is that the circuit breakers are very swift in operation, and of very low amperage (about 5 amps for a 132kV line).
However, the initial high voltage zap through a human conductor, before the circuit breakers kick in, is where the damage occurs.
The circuit breakers on HT lines are designed to prevent system damage, not save lives, as RCD's are designed to do.
The still-intact aircraft cabin in a parachute landing on HT powerlines, would prevent occupants from being zapped with initial high current levels - unlike a regular forced landing, where the cabin is usually severely damaged, and the occupants can be exposed directly to still-live powerlines.
LT powerlines actually pose a bigger threat in crashes, because it takes a higher level of short-circuitry to make pole fuses burn out.
That's why you must always treat downed LT powerlines as live, until you are certain they have been de-energised.