Sometimes the tube goes overground a bit so you can use mobile phones.

It's special.
( Fictional Emma, Fri 1 Sep 2006, 12:40, archived)

See: East Finchley onwards northbound on the northern line.
Also: Lots of bits of district line.
( rosie posie tingly bongly, Fri 1 Sep 2006, 12:47, archived)

Also: about half the length of the Central and H+C lines.
Plus parts of the Circle line, Piccadilly line and East London line.
In fact, pretty much the only one that's entirely underground is the Waterloo and City...

edit: and almost all the Jubilee line north of Baker St and east of Canning Town
( Gizmo.mp3 does not exist, Fri 1 Sep 2006, 12:50, archived)

and there's a spot
at mile end where you think you're underground but you can still use your phone

double-special
( Clairebare Back once again with the Ill behaviour, Fri 1 Sep 2006, 12:49, archived)

Ah, that's because there's actually a small slot up to daylight.
If you stand on the westbound Central platform and look up you can see.

I only realised because I managed to get rained on there once
( Gizmo.mp3 does not exist, Fri 1 Sep 2006, 12:52, archived)

That was just a tramp pissing on your wafro

( Amorous Badger NAKED BEA ARTHUR PHOTOS 4U, Fri 1 Sep 2006, 12:56, archived)

i know
and you missed most of the east and west ends of the District line
( Clairebare Back once again with the Ill behaviour, Fri 1 Sep 2006, 13:00, archived)

Rosie had already mentioned those.
What I entirely missed out was the huge stretch of Metropolitan line out to Amersham/Watford that's entirely open...
( Gizmo.mp3 does not exist, Fri 1 Sep 2006, 13:20, archived)