"The primary aim of the NLE is to encourage economic growth in London and the wider UK economy by facilitating the sustainable regeneration and development of the Vauxhall Nine Elms Battersea (VNEB) Opportunity Area. This includes the creation of a major new sustainable residential, business and leisure district in London’s Central Activities Zone."
"The regeneration of VNEB offers a unique opportunity: the BPS site alone is the largest and last remaining significant development site in central London. The Mayor’s vision for the Opportunity Area is clearly set out and the potential for up to 16,000 new homes and 20,000-25,000 new jobs identified. From an assessment of planning consents, it is clear that the full level of growth is only achievable with the NLE in place."
The Northern line extension is being built because the VNEB development requires a major new transport link and won't be a success without one. According to documentation, TfL explored every possible alternative (Extend the Waterloo and City line? No) (Extend the DLR? No) (New trams? No) (New station on the Overground? Not close enough) (Add a branch from the District line? Very no) and decided that a Northern line extension was the only viable option.
"Within the OA lies the Battersea Power Station building, out of use since 1983, and a Grade II* listed building in need of extensive repairs. A number of attempts have been made to redevelop the site over the intervening years. The most recent planning consent, from LB Wandsworth in August 2011, states that the development cannot proceed beyond Phase 1 without the NLE and commits the applicant to substantial actions to seek to bring it forward, including an infrastructure contribution of £211.6million to the scheme."
We're only getting a Northern line extension because the London borough of Wandsworth has insisted on it. No tube line, no development. This has extracted a lot of cash from the developer, but has also forced TfL's hand.
"The 15% affordable housing option is considered the most appropriate for the majority of the opportunity area’. Policies within the Core Strategies of Lambeth and Wandsworth set affordable housing targets at least 40% and 33% respectively. This reduction in affordable housing is to specifically allow those schemes to make tariff contributions at the higher rate of £20,000 per unit, rather than £15,000 if 40% affordable housing were to be provided."
That's an interesting insight into housing policy. Normally at least a third of housing in new developments has to be affordable. At Battersea there'll be less than half that, because this brings more money to council coffers.
Some facts about the railway
"The two new stations will both be in Zone 2 (as is Kennington station), and are provisionally named ‘Battersea’ and ‘Nine Elms’. There will be a 5-6 minute journey time between Kennington station and Battersea Power Station."
"The NLE will be approximately 3,150 metres long northbound and approximately 3,250 metres long southbound including overrun/stabling tunnels west of the terminus at Battersea, a crossover east of the terminus and junctions serving each of the tunnels to link with the existing railway at the Kennington loop."
The overrun tunnels to the west of Battersea station are important because they allow for a future extension to Clapham Junction. These tunnels will run directly underneath Battersea Dogs and Cats Home, which will be forced to relocate some of its services during construction (including all its operating theatres).
"The NLE is primarily considered as an extension of the Charing Cross branch of the line (rather than of the Bank branch) because:
• connection for the extension can be made from the Kennington loop (which is used by Charing Cross branch trains to turn round), allowing trains to continue to Battersea, or terminate at Kennington and then return northwards from the loop;
• the Charing Cross branch enables construction and operation of the NLE with relatively minor disruption to other train services;
• the Charing Cross branch is less crowded (and forecast to remain so) than the Bank branch;
• the Charing Cross branch allows step-free access to Crossrail at Tottenham Court Road as well as the Central line."
So now you know.
"In the construction phase, a number of short term closures of the Kennington loop will be required, reducing service frequency on both branches of the Northern line. TfL has considerable experience of managing this type of work and it is expected that these will take place over weekends. Additionally there will be some limited disruption to interchange at Kennington station during the construction of the new cross-passages."
There are no clues here to quite how many Northern line closures will be required, but expect the closures at Kennington to break a lot of journeys. Throw in all the upgrade work that's planned at Bank during the same period, and you can expect considerable disruption if you live or work down the Northern line.
Some facts about train services
"It is assumed that the NLE opens in 2020. The second phase of the Northern line upgrade is scheduled to be completed by 2022. This will deliver an additional 38% capacity on the Bank branch and an additional 25% on the Charing Cross branch in the peak direction during the peak hour (8am-9am). The service levels for the NLE are planned to be compatible with this upgrade. In the opening year, this will mean 16 trains per hour in the morning peak hour rising to up to 28 tph after 2022. On the Charing Cross branch of the Northern line, 30 tph are proposed after 2022, with 28 of these to go Battersea and 2 to terminate at Kennington."
This is the long-promised permanent split of the Northern line, at the southern end, with Charing Cross branch trains going to Battersea and City branch trains going to Morden. But do Battersea and Nine Elms stations really deserve a train every two minutes?
Forecast patronage on the NLE, 2031 (am peak period, 7am-10am)
Northbound: Battersea → Nine Elms 4200 passengers; Nine Elms → Kennington 8300 passengers Southbound: Kennington → Nine Elms 6300 passengers; Nine Elms → Battersea 4200 passengers
If these forecasts are correct, there'll be an average of 300 passengers on every train running north into Kennington, and nearer 200 passengers on every train running south. That's quite busy. But not too busy...
"Our forecasts also show that the additional passengers generated by the NLE will not have a significant impact on the Underground network."
TfL reckon that the impact of the Battersea extension will be "minor crowding impacts (imperceptible for an individual passenger)". An extension all the way to Clapham Junction would have been much more useful, but alas much more crowded, so we're not getting one.
Some facts about the benefits
"The economic appraisal has valued the overall benefit of the NLE in terms of transport benefits and its role in delivering additional economic productivity and jobs to London and the UK as a whole. The NLE has a benefit to cost ratio (BCR) of over 8:1, meaning that every £1 spent will deliver at least £8 in benefits."
8:1 is a very impressive benefit to cost ratio. Most public projects deliver considerably less.
"The BCR presented above demonstrates excellent value for money, but does not distinguish between public and private costs. When only the costs borne by the public sector are considered, the NLE represents exceptional value for money. As set out in the following chapter, the NLE is being financed and delivered by the public sector, but the up-front costs will be recouped from the development. Under this scenario, the BCR for the NLE is 196:1."
A ratio of 196:1 is unheard of. Essentially the public cost of the Northern line extension is peanuts compared to the perceived economic benefits it'll bring. It would, therefore, be stupid not to build it. Thank you, developers, for your cash.
"With the NLE, passengers travelling between VNEB and central London will benefit from reduced travel time between 10 and 20 generalised minutes.
(Generalised time is a standard measure of accessibility which includes the perceived impedance associated with walk, wait times and crowding)"
Some parts of Nine Elms and Battersea currently have relatively poor transport connections (for central London), and the Northern line extension will significantly improve this. Battersea is the big important station for all the new development, but the intermediate station at Nine Elms has been sited very deliberately nearer to the existing community so that they don't lose out.
"The estimated outturn cost of the Northern Line Extension has undergone a number of reviews since the project was transferred to TfL. Currently, the NLE scheme is estimated to cost £868m in 2012/13 prices, which includes a contingency of 22% of the prime cost. The outturn cost, which adds forecast inflation to this figure, is estimated to be £998.9m, and represents the amount that will need to be financed."
I think we can assume that the public inquiry into the Northern line extension will come out in favour. Come back in 2020 and we'll see how much the extension actually cost, and how many passengers really want to travel this way.