Leytonstone is on the Central (Red) Line. It is on the overground part of the line.
I was out there taking part in an Orienteering event on Wanstead Flats.
The Flats are quite scrubby so there some of the areas we were running in were quite difficult, but it was quite good fun - after the event the pub we were all in (O'Neills) was holding it's weekly Quiz Night. Our team came 3rd.