Victoria Line - why & where do the lines switch sides?

[OLJR]

Heading northbound from Pimlico to King's Cross-St Pancras the doors open on the right hand side and a passenger walking straight out and through the atrium will find herself on the other platform.

At King's Cross however the northbound service's doors open on the left hand side yet a passenger walking straight out and through the atrium will again find herself on the other platform.

This means that the north and southbound lines cross across each other somewhere between Pimlico and King's Cross-St Pancras.

Does anybody know why and where this happens?

Many thanks in advance!

 

[Kingsbury Jn.]

It is between Oxford Circus and Warren Street
http://carto.metro.free.fr/cartes/metro-tram-london/index.php?station=pimlico

 

[swt_passenger]

It's all about the way cross-platform interchange with other lines was practically constructed at individual locations. You have to consider that the other lines were already there, so the Victoria line had to be superimposed onto the existing system somehow.

As I understand it the key issue was how the cross platform interchange was designed at Euston - this required the Victoria lines to be transposed so that the cross platform pairs are northbound and southbound. So there has to be a left/right 'crossover' either side of Euston somewhere. The best engineering solution found was to have RH running at both Warren St and Kings Cross, because there was more room for the 'crossovers' (in terms of route length) between the next pairs of stations.

The line diagram on the website "Clives Underground Line Guides" helps to make sense of the above explanation: http://www.davros.org/rail/culg/victoria.html#layout

 

[CarltonA]

You may notice the Jubilee line swapping sides in the Baker Street area too. This is because of interchange with the Bakerloo line which had three platforms there between 1939 and the Jubilee taking over the Stanmore branch. The Central line also swaps sides in the White City area for reasons connected to the original depot and terminus in that area.

 

[tsr]

Of course, to get back round the other way, the Victoria Line tunnels cross over again between King's Cross St Pancras and Highbury & Islington. You can feel the gradients if you are very observant and/or familiar with the line.

 

[edwin_m]

The Victoria did more than any other Tube line before or since to get cross-platform interchange. At several places tunnels were taken over from other lines to achieve this, with new bits of tunnel being bored for the other lines (including some large-diameter ones for Highbury & Islington).

The Northern also runs on the right from north of Bank to south of Borough, and the Central Line tunnels are one above the other at St Pauls and Chancery Lane. In both cases I think this was because of staying within the footprint of the street above, to avoid paying compensation for running beneath people's property.

 

[jopsuk]

it matters a bit less with tube lines compared to surface (or even subsurface) whether it is right hand running, left hand running or even, as mentioned, superimposed. There's a certain level of freedom afforded in being able to go up or down relatively easily (ie you're already building a tunnel/no need for bridges) with no real additional constraints- you're already considering street footprint, foundations, existing tunnels. So switching for better interchange is useful- eg at Euston both the city branch Northern Line and Victoria Line "northbound" platforms are together despite locally the trains running in opposite directions!

 

[Peter Mugridge]

There are a couple of sections of the Central Line where the tunnels are directly above each other - again I think that's to do with keeping the "footprint" narrow when the line was built?

 

[spinba11]

The Jubliee line tunnels go on top of each other at Westmister.

 

[grid56126]

The other really clever idea at a number of Victoria line stations was the use of gradients prior to and departing from stations. You can see this at a few locations where trains arriving come in "uphill" - less braking required and depart "downhill" - quicker more efficient acceleration.

 

[Abpj17]

The Northern also runs on the right from north of Bank to south of Borough, and the Central Line tunnels are one above the other at St Pauls and Chancery Lane. In both cases I think this was because of staying within the footprint of the street above, to avoid paying compensation for running beneath people's property.

Yup, the area is heavily built up with some buildings having deep excavations (particularly those with gold vaults etc.). The proposals for Bank will involve building a new tunnel /platform for the southbound line and merging the current north/south platform into one.

Long discussion of details: http://www.londonreconnections.com/2012/bank-station-upgrade-part-2-of-2-the-proposals/

 

[edwin_m]

The other really clever idea at a number of Victoria line stations was the use of gradients prior to and departing from stations. You can see this at a few locations where trains arriving come in "uphill" - less braking required and depart "downhill" - quicker more efficient acceleration.

The Central Line is probably the best example of this - it is pretty straight so you can often look into the tunnels and see the track sloping away. It's got more difficult with later Tubes because there is so much other stuff in the ground to avoid, but I think Crossrail does the same at some stations.
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Yup, the area is heavily built up with some buildings having deep excavations (particularly those with gold vaults etc.). The proposals for Bank will involve building a new tunnel /platform for the southbound line and merging the current north/south platform into one.

In Edwardian times it was true everywhere not just where there were bank vaults. Tunnelling under someone's property involved paying them for the privilege, even if there was no damage caused. This was changed at some stage later on.

 

[Busaholic]

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In Edwardian times it was true everywhere not just where there were bank vaults. Tunnelling under someone's property involved paying them for the privilege, even if there was no damage caused. This was changed at some stage later on.

With fracking in mind, it's possible the law may be changed back again.

 

[PeterY]

According to my Quail atlas the Northern also has right hand running at Kentish Town.

Does anyone know the reason?

 

[astock5000]

The Northern also runs on the right from north of Bank to south of Borough, and the Central Line tunnels are one above the other at St Pauls and Chancery Lane. In both cases I think this was because of staying within the footprint of the street above, to avoid paying compensation for running beneath people's property.

The reason for right hand running at Bank is a bit more complicated than that.

The City & South London originally terminated at King William Street, this is shown on the Carto Metro map linked to earlier in this thread. As you can see, the tunnels are one above the other immediately after they turn to the south (due to a narrow road above), and both needed to be much lower than the station to get under the Thames.
The eastern tunnel under the river becomes the upper one, so this had to be the northbound line because the gradient up to the station from the lower tunnel would have been too steep. This resulted in right hand running, and the tunnels couldn't be swapped back until south of Borough. The same situation occurred when the line to Moorgate was built, it was not possible for the tunnels to cross over until north of Bank. That was possibly due to the old tunnels being above the line as far as London Bridge.

 

[OLJR]

A fascinating set of replies. Thanks very much to all who posted.