Paul Weaver wrote:

A colleague of mine did successfully jump the middle track at White
City, which seems rather stupid being DC lines (I believe current
should be switched off in stations when a train isn't approaching, not
something I'd risk though)

When you say "current should be switched off" I'm unclear as to
whether you mean that is how you think it should work in an ideal
world for added safety, or whether that is actually how you think it
does work right now.

Because UIVMM the current most certainly isn't switched off in
stations when a train isn't about, the live rails remain live all the
time - train or no train.

Which makes what your colleague did pretty reckless. I wonder if he
did it under the false impression that all would be well even if he
did fall and hit the live rails?