(Sorry to go off topic)
Why is it that birds can sit on a 25kv line and not get cooked? If I touch it then I'm history!!
Because the electricity isn't earthed by the bird. It'll only get cooked if it makes an earth connection, so the current could flow through it.
However, a person jumping onto the wires would have to be near a pole or wall or something, so the current can flow through the person and too the ground, thus cooking the person. Lovely.
Mind you, when the wires are close to the train, a pidgeon can accidently earth the current from the wire to the train to the ground. I believe this happens often at Kings Cross Thameslink.