Tunnel closure

[programmes1]

Can anyone explain why the Bakerloo was closed for some months in 1996/7 what work was being carried out?

[21146]

Wasn't this work on the crossovers at Elephant & Castle, which meant reversing at Piccadilly Circus? There was then a derailment at the latter which cut the line back to Paddington.

[superteacher]

I'm sure they were doing something with the tunnels which run under the Thames.

[Tubeboy]

I agree about the work being Piccadilly Circus crossover, but I do now recollect some closure regarding the floodgates a few years back?

[programmes1]

Looked on google and found that between Nov 96-July 97 line was closed due to tunnel strengthening, now I know that between Waterloo and Embankment there was Armour plating put in WW1? was this the work done in the closure?

[abe]

The cement behind the armour plating had turned to mush. In addition, the tunnels were so close to the river bed that there was a concern that, were a boat to sink and hit them that they would be ruptured.

The work involved concrete piles being sunk alongside the tunnels, and a concrete cap being placed above the tunnels. The tunnels were sealed either side of the work, but I'm not sure that this involved the WWII floodgates. Other work (e.g., Elephant crossovers) might have been done at the same time, but the principal reason for the closure was the tunnel work.

[Deleted]

IIRC, the German propaganda machine alleged that the tunnels were receiving attention because of a bomb hit - when in fact it was a defence measure.

[Deleted]

Aug 19, 2008 15:14:54 GMT programmes1 said:

Looked on google and found that between Nov 96-July 97 line was closed due to tunnel strengthening, now I know that between Waterloo and Embankment there was Armour plating put in WW1? was this the work done in the closure?

Yep it was tunnel strengthening project, I was a driver on the Bakerloo at the time.

Edited to add: I actually qualified as a driver during TSP, June 1997 to be precise, and I (along with all drivers who qualified during the closure) had to have road training Picc to Elephant on the weekend before it re-opened for passenger service.

Also, because of TSP and London Rd Depot being unavailable, a number of Bakerloo trains were kept at Neasden depot for the duration, and a special night link of T/Ops had duties purely to transfer this stock backwards and forwards between Neasden and Stonebridge Park (rather than leave the same trains up there for 8 months). So I also did my stock training at Neasden depot.

[programmes1]

Thanks for all the replies really interesting just one question is the Armour plating still there?

[abe]

No, I *think* it was removed, the new concrete being deemed acceptable for protection.

[Deleted]

I suspect that LU now thinks it unlikely that bombs will be dropped in the Thames.

[abe]

A bit more on the armour plating...

Due to the lack of steel in WWI, it was only in 1919 that the plating was fitted. A 540 ft length of the SB tunnel, and 480 ft length of the NB tunnel had ½-inch steel plate installed. Below the tracks the plate was ¾-in thick, with concrete grout below. To accommodate this and keep the trains at the right height the track was replaced by bridge rails on longitudinal sleepers.

By WWII, water ingress had affected the invert concrete, and the tunnels were closed for 11 days to remove the invert plates and concrete, and putting standard track back in. The upper portion of the armour plating was left in position, supported on new corbel plates. The floodgates at the north end of Charing Cross station were closed, and a temporary waterproof diaphragm installed at Waterloo.

[Deleted]

As I understand it, the work was with the under river tunnels. Work was also done at htis time between London Bridge and Bank on the Northern line, I believe this was to complete an identical job as the Bakerloo line closure, to stabilise the tunnels against the river.