Hey.
So I see you’re thinking of doing this RP in London, just wanted to say that I don’t think that it’ll work very well.
The reason why metro 2033 worked so well was because it was the underground in Russia, considering most of their major Underground’s were built to double as nuclear shelters, as backed by the hermetically sealing doors in most stations.

London’s tube network is much older and doesn’t have nearly the sophisticated defences in place that Moscow’s did, the lack of hostile wildlife (bears and wolves) and without a doubt the lack of guns or ammunition would make it really difficult to work well.

This is just in my opinion of course- but if you wanted to do somewhere else- there’s St Petersburg, that has a similar construction to Moscow’s metro and the same goal in mind, as well as being mentioned briefly in the books.