The Anonymous Widower

Are There Any Other Places Where A Loop Extension With Stations Can Be Built?

I said this in my piece on the Northern Line Extension.

Reversing loops with stations are not unknown in the UK. Terminal 4 at Heathrow is served by the Piccadilly Line in this way and the Merseyrail Loop Line, is a larger example, that reverses and provides several stations for the Wirral Line. It could also be argued that Bank station on the Docklands Light Railway is two platforms on a reversing loop.

But are there any other places, where a loop extension with stations could be built to advantage?

The great advantage of the reversing loop layout for an extension, is in the construction phase.

1. Only one continuous tunnel needs to be built, which can be built with one tunnel boring machine (TBM).

2. Crossrail has shown that TBMs can be controlled to a high-degree of accuracy, which enables optimal loop tunnels to be created, going deeper than traditionally if necessary.

3. Simple stations can be built by connecting the out and return legs of the loop together and then adding lifts and escalators to the surface.

4. Simple one-platform stations could be built on the outer reaches of the loop.

5. It might be possible to reduce the number of shafts dug to the working tunnel. This would surely help in a crowded city.

6. There is only minimal disruption to existing infrastructure during the construction.

These are some places, where the loop extension with stations might be used.

Bakerloo Line Extension

There have been lots of proposals for the route of the Bakerloo Line Extension. Some are just simple ones taking the line to Camberwell and some envisage the line taking over the Hayes branch.

I have seen discussions about the latter and some have flagged up all sorts of problems, like how do you provide a service during the construction period.

So the design of this is going to be difficult. But I wouldn’t rule out an out and return loop going via Camberwell.

This links to my proposal.

Extending The Docklands Light Railway Westwards From Bank

There have been two proposals for this.

1. Charing Cross/Victoria

2. Euston/St. Pancras

Would these best be served by extending the loop tunnel at Bank appropriately?

Possibly, but does the DLR have enough capacity for either of these services?

Extending The Docklands Light Railway Southwards From Lewisham

There have been two proposals for this.

1. Beckenham Junction

2. Bromley North

Perhaps an underground loop could be used to turn trains at Lewisham, that served several stations, south of the current terminus.

Jubilee Line

Extending the Jubilee Line eastwards from its orignal terminus of Charing Cross could have used the reversing loop technique to take in stations in the eastern parts of the city in a wide loop. But in the end the Jubilee Line Extension was built to Stratford.

Extending The Jubilee Line To Thamesmead

In the design of North Greenwich station on the Jubilee line, provision was left for a branch to Thamesmead.

It is not in any plans at the moment, but a reversing loop could be built covering Charlton, Plumstead, Thamesmead and Abbey Wood.

Extending the Gospel Oak to Barking Line from Barking Riverside To Abbey Wood

This is an aspiration of Transport for London. But could it be dug in a single extended loop from Barking Riverside? The biggest advantage would that incorporating a single underground platform at Abbey Wood, would be a lot easier and affordable, than creating a full terminus there.

Extending The Victoria Line Southwards To Herne Hill

This is mentioned under Possible Future Projects on Wikipedia for the Victoria line. This is said.

For many years there have been proposals to extend the line one stop southwards from Brixton to Herne Hill. Herne Hill station would be on a large reversing loop with one platform. This would remove a critical capacity restriction by eliminating the need for trains to reverse at Brixton. However, it would be expensive and cannot currently be justified on cost-benefit grounds. Because the current line is heavily overcrowded this is considered to be the only extension proposal with any realistic prospect of coming to fruition; but to have any hope of being built, it would have to be seen to be effective in reducing overcrowding (by enabling trains to run more frequently) and not to increase it.

But it strikes me that if TfL’s engineers find better ways of building these loops and their stations, perhaps it could be built to increase capacity on the Victoria line.

Outside Of London

Outside of London, I don’t know the railway infrastructure, like I do in London, but I’m sure that the concept could be used elsewhere.

 

 

November 16, 2014 - Posted by | Transport/Travel | ,

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