Doctor in training and tier 2 (general) visa

[sonic22hedgehog]

I am a doctor working in tier 2 (general) category.

if someones gets a ST3 post and has to apply for a tier 2 (general) visa to get it,
will they have to renew it every time they goto a new hospital?
or do they get one tier 2 visa for the whole time of training? how does it work?

is tier 1(general) visa open for people who are applying from tiers 2(general) within UK?

anyone who has got into ST3 training through a tier 2 visa,or anyone else who has knowledge on the matter, please help

thanks!