I work on the cctv, so I spend most my time replacing camera's the stuff ruins, its mainly brake dust, dead skin, that sort of thing, its not the nicest thing in the world to be covered in (ive seen people come out black head to toe after opening a panel on the platforms).
Bakerloo is the worst for it (I swear theres a bloody coal factory at each end!)
3 lines which I've narrowed down as being the worst, are:
#1 Victoria
#2 Bakerloo
#3 Central


Even in the depths of mid-winter its somehow hotter than a reaaalllly hot oven on the central line tubes
Then again I don't seem to have any snot 

