Should the JLE have been a separate line?

Had the extension been opened with the moving block signalling then the service would I think have been better. Instead old kit off the Central line was put in, just in time to open for a New Years party at a large tent in south east London.

Was the west end of the line originally going to always remain signalled from Baker Street though or was it going to all go to Neasden? I don't think that lever frames can do moing block!

I suppose that was one way the line wasn't necessarily future-proofed?

Narrow platforms? Where?

I'd say Westminster is another candidate of narrow platforms as it does look narrower than London Bridge?

Nothing wrong with these platforms! And there are the doors to stop people falling on the tracks!!

The cost of the project is all in mobilising the manpower and machinery to make it happen - excavating a bit more soil once they were there would have added a negligible extra cost in the greater scheme of things. It was madness to go to all that effort to build such small tunnels and such short platforms.

But when were these calculations last done? I'm guessing it was when the original Jubilee Line was being planned, as once the decision to extend a tube line has been taken you're pretty much stuck with that loading gauge.

Personally I would have liked to have seen the Jubilee run through the docks and turn south from Silvertown / City Airport to serve Woolwich and Thamesmead and terminate at Dartford.

The discussion on tunnel sizes has brought up a few good and a few not so good arguments. The idea that you dig a tunnel and make it any size with just a little further effort don't work too well. The poor old guys removing the extra spoil will also have to return with a considerable number more of the tunnel segments. This has a major bearing on the logistics of the tunneling and the fabrication and storage of the segments. The need for more sites along the route will likely to also require extra tunneling shields to ensure that the line is completed to the original timescale.

The thought on the size has been a major factor in the early years of UndergrounD railways and the Met & Dist were only built with the cut & cover method as they could be built relatively quickly as labour was cheap and 200 brickies and 20 million bricks was also relatively cheap. The need to not run under property in those days also meant that relatively sharp curves were introduced which lent to short wheelbase coaching stock. The development of the size of tube tunnels has not been all that straightforward as the original CSLR was reconstructed to the size of the CCE&H tunnels on formation of the Northern line. With the advent of modern tunneling techniques and the removal of the need to not pass under property has allowed the advent of longer curves allowing higher speeds and longer tube cars.

London Bridge looks fine to me. The reason Canary Wharf, North Greenwich, Canada Water are wider is because they were built by cut-and-cover. London Bridge and Westminster are bored with TBMs and the latter had to be narrow to avoid subsidence to the Houses of Parliament.

The biggest costs in a any job like that are generally real-estate-related, not the physical items.
also, the cross-sectional area isn't doubled.
Costs of materials like concrete and so forth are significant, but nothing compared to land, and labour.

The economics are not as you'd think - or Crossrail would be an order of magnitude more expensive with some siginificanlty bigger tunnels

Knowing what ducatisti does for a living I'd say that he's got a pretty shrewd idea of the economics and where the costs come from.

So who's gonna break in and steal the Bills of Quantities?

That 3x cost - is that /mile or overall?
Has inlation/prices rises etc been put in (copper for example has gone up by Something Silly)
Strip out all the newly required features (eg DDA requirements, increased security etc

Do we know how much they are factoring for property blight? Crossrail goes through some more expensive areas than the JLE, and IIRC property blight is related to both the value of the building (which will be higher in the city as they are bigger) and commercial value (also higher becuase of rents etc).

there again, they should be going through more predictable underground geography (is it geology when there's not a lot of rock? where does geogrpahy stop and geology start?)

ATO will solve some capacity problems to an extent but only if it is more reliable than the current signalling. Crossrail will also help when it is completed.

Are the tunnels on the JLE built to 14' 'enhanced' size, and is this the same as the tunnel size on the victoria line?