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Finish Ringway 2

Cut-and-cover some South London railways and put an expressway on top
  [vote for,

London's ringways scheme devised in the 1960s saw a series of new motorways enveloping the capital, of which only one loop was ever completed - the M25, which is a combination of bits of the outermost ringways 3 and 4.

Ringway 2 was planned to go through the suburbs about half-way between the centre and the farthest reaches of the city, and was successfully built in the North and East, as the North Circular road. However, the South section was never built, making any vehicle journey through South London very difficult to this day.

Historically, South London has had many more overground railway lines compared with North London because the geology made tunnelling difficult. However, technology has progressed and this isn't much of a problem any more.

The many miles of existing railway corridors slicing up South London, combined with a lack of existing tunnels, gives rise to the possibility of rebuilding some of the railway lines underground using cheap, shallow cut-and-cover tunnels. A new four-lane (two in each direction) expressway could be built in the 16 - 20 metres of space freed up on the surface, thus completing ringway 2 with only a few demolished buildings, instead of the ~6000 that would have been cleared in the original plans.

Some of the neighbourhoods that the road would pass through are likely to be habited by influential NIMBYs who do not like the prospect of increased noise pollution. In such areas, the expressway and railways could swap over, with the road underground and the railway remaining on top. Of course, these neighbourhoods would have fewer access junctions to the tunnels meaning they would not be well served by the expressway, but as road haters I don't suppose they would mind.

idris83, Mar 19 2011

Unfinished London Episode 2 http://www.youtube....watch?v=yUEHWhO_HdY
Short documentary about London's unfinished ringways [idris83, Mar 19 2011]

Google Maps ringways overlay http://goo.gl/iYvkh
A Google Maps overlay showing all of the motorways proposed in the 1960s [idris83, Mar 19 2011]

The South Circular - reborn http://goo.gl/0xGPh
A Google Maps overlay I made showing where the new expressway might be built [idris83, Mar 19 2011]


       Nah, I was thinking they could build a new airport south of the river and have some Boeing C-17s shuttling cars back and forth between it and City Airport.
idris83, Mar 19 2011

       // shuttling cars back and forth //   

       Did anyone mention a trebuchet ?
8th of 7, Mar 19 2011

       A trebuchet and castle wall on the opposite bank to catch the vehicles would be more efficient I suppose.   

       More sensibly, the Woolwich Ferry could be replaced with another ferry which is 308 metres long. That way it wouldn't have to shuttle back and forth, but could just sit in the river and cars could drive on one side and off the other. In order to avoid inconvenience to boats wanting to pass, a new Woolwich Land Ferry could be introduced to shuttle boats on the back of a lorry around the obstruction, or alternatively the river ferry could be a hovercraft thus allowing river traffic to pass beneath its skirt.
idris83, Mar 19 2011

       How about a Woolwich Tunnel that the Thames could flow through (East - West), complete with boats ? The syphon effect would ensure that the river levels on each side were maintained.   

       Obviously, the Woolwich flood barrier might get in the way, but that would be easy to demolish.
8th of 7, Mar 19 2011

       If only the great fire happened now rather than all so many years ago. Lots of room for roads if there were no houses at all...
saedi, Mar 20 2011

       There's plenty of room. They just need to move the railways underground.
idris83, Mar 20 2011

       //beginning stub of a bridge// Or the runway of a proposed vehicle railgun/slingshot?
Jinbish, Mar 20 2011


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