[Ulrich Kinbote]

I've seen them around a lot. Something to do with electricity? Telecommunications?



[Ignore cricketers -- photo from unrelated New York Times article on Pakistan/England test match]

[Doofy]

On first sight I'd have said it's a collapsed gas storage tank, but it looks like there's too much metalwork for that.

[Ulrich Kinbote]

I feel a conspiracy theory coming on.

[Mastrap]

It's an empty gas* storage tank. There are tons of them in London. The one in the picture is next to The Oval cricket ground.
These here are behind Kings Cross:




* Gas as in natural gas, not gasoline.

[Ulrich Kinbote]

Originally Posted by Mastrap

It's an empty gas* storage tank. There are tons of them in London. The one in the picture is next to The Oval cricket ground.
These here are behind Kings Cross:




* Gas as in natural gas, not gasoline.

So it was the trussed support for a gas tank? How is it possible to demolish the tank and leave the frame intact? And why remove the gas tank and leave the frame anyway? Why not remove both at the same time?

[Doofy]

Originally Posted by Ulrich Kinbote

So it was the trussed support for a gas tank? How is it possible to demolish the tank and leave the frame intact? And why remove the gas tank and leave the frame anyway? Why not remove both at the same time?

No, no. They're still active, just empty. The tanks "collapse" when they're empty and expand when they're filled.

If you look at your original photo, right at the bottom of the framework you'll see a very light green convex surface. That's the top of the tank, waiting to be raised when there's some gas in there.

Here's one half full:



When collapsed, the upper section fits inside the lower section.

[C.A.T.S. CEO]

Originally Posted by Doofy

No, no. They're still active, just empty. The tanks "collapse" when they're empty and expand when they're filled.

If you look at your original photo, right at the bottom of the framework you'll see a very light green convex surface. That's the top of the tank, waiting to be raised when there's some gas in there.

Here's one half full:



When collapsed, the upper section fits inside the lower section.

Are they big balloons?

[Doofy]

Originally Posted by C.A.T.S. CEO

Are they big balloons?

No, telescoping metal. Like a fat version of the old telescopes.

[jckalen]

think of it like a gravity pump... the weight of the tank puts pressure on the gas to move it along instead of having motors or pumps do the work.

[davesimondotcom]

Looks like the OP was sort of correct - that at least one of the towers that make up the tank is a cell phone tower. Dual use... those Brits are always so clever.

And Mastrap - of course gas as in natural gas. Otherwise you'd have said "petrol" since you were talking about something near London.

[ghporter]

The power distribution system in the Houston, Texas area is frequently used by cell carriers for their towers. It's a smart idea, since the device is already there and doesn't require any new permits for the structure.