What is this...? (Central Line, London Undergroud)

[dogof2head]

Hi folks, firstly many apologies if this is the wrong place to post this and secondly excuse my ignorance. I know very little about the railways, so...

From an A40 slip-road I often see this circular brick structure by the Central Line, just west of White City. It's actually directly under the A40 fly-over over Wood Lane.

http://img304.imageshack.us/img304/2540/dsc002854hl.jpg

Now, I just can't help wondering - what the heck is it??
Or is more A40 related than Central Line perhaps....?

Cheers!

[swisstrains]

Hello and welcome to the forum.
Don't worry if your knowledge of railways isn't too good as we are all here to try and help each other.
I wonder if the circular structure could be some sort of silt collection pit for the trackside drains on the Central line or the surface drains on the surrounding road network?
Hopefully one of our members will be able to come up with the answer.

[Ian White]

I have never come across any thing like that before,not too sure what it is really but it has more than likley got something to do with drainage of the track
All the best,Ian

[dogof2head]

Thanks guys! I caught another glimpse today as it happens, and there's a kind of gulley running though middle - you can make it out in the pic. So some sort of drainage thing would make sense.

Oh, and the more i think about it, the more odd little railway questions i have!

cheers,
tim.

[Shed Cat]

Mystifies me too.

The odd questions are the most fun. Much better than the predicable:- "What colour should they paint[insert loco name here]?"