RAENORTH wrote:
Pre war, as I recall, the tubes had been fitted with huge flood gates. Those, I think, would have sealed off any areas liable to flooding. You can still see the gates in some of the stations.
Oh, oh.... When you have time I really think you should take a look at the link I provided.
In short (and I agree, he certainly likes his trains):
Quote:
On the morning of 10 September it was realised that a potentially catastrophic danger to part of the Underground network had occured during the night.
In 1914, the original section of what is now the Charing Cross branch of the Northern line was extended to a new terminus at the then Charing Cross station (now Embankment) on the north bank of the Thames. Rather than reversing, trains were turned by means of a wide clockwise loop tunnel, part of which passed under the River. A single platform for both alighting and boarding was provided on the final part of the loop before the tunnel straightened out again on a northern alignment. A ventilation shaft also linked the loop to the sub-surface District line tunnels above.
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Quote:
The new trackwork was not connected to the loop, but the tunnel was retained for ventilation purposes by means of the shaft to the District line, and so not completely sealed off, although watertight bulkheads were installed on the river side of the ventilation shaft, and where the other end of the loop met the new southbound tunnel, numbered 13 & 14 respectively.
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Quote:
During the air raid on the evening of Monday 9 September 1940 - possibly around 23:25[2] - the schooner Seven Seas, moored on the north-east side of Hungerford Bridge, was rocked by the detonation of a 50kg High Explosive (HE) bomb that landed in the River. The crew reported that, "the water appeared to spout up for some 30 seconds after the explosion," caused by air escaping from the ruptured loop. It was later discovered that water was seeping through bulkheads 13 & 14, further indicating that the disused tunnel had been breached.
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It took until the 20th September for divers to inspect the tunnel.
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Quote:
A considerable quantity of ballast and mud was lying inside, to a level of around 3-4 feet (1 metre) above the original track level, and the loop between the bulkheads was completely flooded. The extent of the damage was clearly worse than expected, as it was apparent that another bomb landing in the vicinty could cause a "water hammer" effect through the flooded tunnel that would easily breach the bulkheads, flooding the southbound running tunnel, and also the District line via the ventilation shaft.
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Quote:
Work on the loop tunnel continued, with the plugging of the main breach being finished by Wedneday 6 November, the waterproofing of the disused passageway on the following day, and the construction of the new bulkhead some time after Tuesday 12 November.
(Sorry, for this interruption.)
) despite the fact that I only found it a few minutes ago - forget the rest of this post. However, on the odd chance that it has passed you by, the blogger has a whole section on the London Underground at war (The London Underground on this day 70 years ago...) 