This article outlines Crossrail 2 Swirl, an alternative to the flawed "Balham Bulge" plan put forward by TfL (Transport for London) in South West London. As we'll see, Swirl is both cheaper and more effective than TfL's plan.
Update 2015-12-10: This article is effectively part 1 of 2. The Swirl plan below proposes a fast line tunnel under Wimbledon. The Swirl-Max plan proposes how Swirl can be extended to serve Balham, Tooting and Streatham. See also my previous articles on Crossrail 2. And follow up on journey times.
TfL plans for Crossrail 2
This map outlines the current TfL plan for Crossrail 2 between Clapham Junction and Wimbledon, via Balham.
As can be seen, the "Balham Bulge" route from Wimbledon to Clapham Junction via Balham is very indirect. In addition, the chosen tunnel portal site to the north east of Wimbledon, requires the demolition of most of Wimbledon town centre, including the Centre Court shopping centre (everything along the purple line on the map is demolished). The Swirl plan removes the ineffective Balham Bulge and avoids the need to demolish Wimbledon town centre.
For more details on why a Balham routing will not be effective, see the previous article on how TfL's plans make the Northern Line overcrowding worse not better.
Crossrail 2 Swirl
Crossrail 2 Swirl is a proposal to alter the route and design of Crossrail 2 between Clapham Junction and Wimbledon. Instead of serving Balham or Tooting, Swirl serves Earlsfield, hence the name - "SW EARLsfield".
To provide the total capacity increase needed for South West London, Surrey and Hampshire, a total six tracks are needed from at least New Malden to Clapham Junction. To provide this, Swirl proposes a tunnel from the A3 between New Malden and Raynes Park all the way to Clapham Junction and beyond, giving four tracks on the surface and two tracks in tunnel. Between the junction at New Malden and the A3 tunnel portal, six tracks would be provided by removing the fast line platforms at New Malden.
The A3 tunnel portal site has a key advantage over TfL's Gap Road site in that it has excellent road access. Being able to send heavy vehicles down the A3 to the M25 will have major benefits for local roads.
All fast line services from Surrey, Hampshire and beyond would run via the new tunnel under New Malden, Raynes Park and Wimbledon. No underground stations are needed on this section as these are the fast lines. The existing four tracks through Raynes Park on the surface would be used for Crossrail 2 and outer suburban services to Waterloo.
At Wimbledon, the existing six platforms would be retained. A new footbridge would be needed to cope with increased usage, but the rest of the town centre would be completely unaffected. Crossrail 2 trains would use the existing slow line platforms. The outer suburban services to Waterloo would use the existing fast line platforms, providing a cross-platform interchange. This will allow passengers to change to a high frequency Waterloo service (TfL proposes an interchange to a much lower frequency Waterloo service).
In order to provide a high frequency service through the core of Crossrail 2, it is necessary to turn back some trains at Wimbledon. This would be achieved using the existing Thameslink platforms, with the tram evicted to run at street level. Thameslink services would share the platforms.
The key part of the Swirl proposal is the very large Weir Road industrial site between Wimbledon and Earlsfield. This would be used to "swap" usage of the tunnel. The fast tracks would be taken out of the tunnel and back to the surface to use the existing surface tracks to Clapham Junction. The same site would also be used to take the Crossrail 2 tracks down into the tunnel. As a result, Earlsfield station would be replaced with a sub-surface station.
Note that the proposal is for a single tunnel all the way from New Malden to beyond Clapham Junction using a single Tunnel Boring Machine (TBM). While this may seem strange, the costs associated with tunnelling tend to be at the tunnel portals, with the distance that the tunnel is driven being a secondary consideration. As such, it is cheaper to have a single TBM rather than two separate tunnels. The "swap" at Weir Road involves a relatively simple cut and cover box that would be built after the TBM had passed through the site.
The Crossrail 2 Swirl proposal has minimal impact on the branches that can be served by Crossrail 2 in outer London. As such, the map of services below shows the same branches as TfL's official scheme:
However, unlike the TfL scheme, none of the outer suburban (green) services need to stop at Earlsfield or Raynes Park, providing a faster journey for many passengers. It should be noted that only those outer suburban services to Twickenham would stop at new Malden.
The Swirl proposal has the following benefits compared to the TfL plan:
- £1.5bn cheaper (estimated)
- Much better service for Earlsfield
- Better services to Surrey, Hampshire and beyond
- No need to demolish the entire centre of Wimbledon
- Tunnel portal with direct access to the A3 for lorry traffic
- Does not worsen the overcrowding on the Northern Line
The cost estimate is very rough, but there is no doubt that Swirl has a lower cost than TfL's plan. The total length of tunnel from New Malden to Clapham Junction is just 1km longer than the indirect tunnel from Wimbledon to Clapham Junction via Balham. This has an extra cost of about £100m. The sub-surface station at Earlsfield should be cheaper to build than the tunnelled station proposed for Balham, saving perhaps £100m. The tunnel "swap" is again a relatively simple construction, perhaps £200m. The primary difference is therefore is the large amount of work avoided at Wimbledon.
At Wimbledon, TfL is currently planning on demolishing the entire town centre. The main covered shopping mall, Centre Court, and many more buildings would be demolished to allow an additional four platforms to be built along with a long cut and cover box. The disruption caused will be immense. It is very hard to estimate the cost of this work, however £2bn does not seem like an unreasonable estimate. By contrast, Swirl requires minor changes to the existing station, plus some new tram tracks, for a far lower cost.
The Swirl plan provides better services to outer suburban services such as Surbiton, Claygate, Walton and Guildford. This comes from the ability to provide more services now that the outer suburban trains do not need to serve Earlsfield. These services will also save time without the need to stop at Earlsfield.
Swirl provides a better service to long distance services from places such as Portsmouth, Basingstoke, Winchester and Southampton. The benefit here is that the fast services will run via the new tunnel between New Malden and Earlsfield. The new tunnel will have a higher speed limit than the existing fast tracks on the surface. As such there would be a small journey time saving (which cost-benefit calculations tend to place a high benefit value on).
At Earlsfield, the new sub-surface station can be constructed south of the existing station and double ended (two exits, one at each end). This would provide an exit from the station to the far end of the Weir Road site. Assuming that the Weir Road site is still used for a train depot, there is no reason why the depot cannot be covered with a concrete deck. This allows the site to be used for massive development, with enhanced value thanks to the new station entrance/exit.
Update 2015-11-29: This section was added to provide some additional notes on Swirl primarily for TfL and Network Rail.
Swirl proposes the "tunnel swap" occurs at the Weir Road site. This is because it is known that the site is large enough at 1km long. However, there would be cost benefits to perform the swap north of Earlsfield alongside the cemetery. This is a much narrower site however. If the prison becomes available for redevelopment, it may be possible to use that site to make this alternate swap location more practical.
Swirl proposes the tunnel portal next to the A3 at New Malden. This is good for road access, but not the easiest in construction terms. The next possible portal site is north-east of Berrylands station, on the east side of the river north of some housing. That site has less good road access, but is completely off the railway, potentially making it easier to construct. A proper engineering analysis would be needed to compare the two sites.
Swirl has two elements - a fast line tunnel under Wimbledon and serving Earlsfield instead of Balham. It should be noted that the fast line tunnel part of Swirl is compatible with serving Balham, although the author does not believe that to be the best approach.
Relieving the Northern Line
Update 2015-12-10: Since serving the Northern Line is critical to Crossrail 2, the Swirl plan has been extended into the Swirl-Max plan, which serves Earlsfield, Balham, Tooting and Streatham. Swirl-Max is the version to be submitted to the TfL consultation.
Originally, this article proposed that the Northern Line could be relieved by extending the Northern Line Extension (West End branch) from Battersea Power station to Cedars Road on the Clapham/Battersea border and on to Clapham South and/or Balham. This option has now been dropped as further analysis showed it would not work.
Crossrail 2 Swirl is a detailed plan to provide a better solution for South West London, Surrey and Hampshire. It proposes a single tunnel from New Malden to Clapham Junction and beyond, with a tunnel "swap" between Wimbledon and Earlsfield. This avoids the need to destroy Wimbledon town centre, and saves around £1.5bn in the process. See the Swirl-Max plan for how Balham and Tooting would be served.
The October 2015 consultation is now closed, but readers are encouraged to continue to speak to politicians and others in power to fight for a better option for Crossrail 2. Use the term "Fast Line Tunnel" or "Crossrail 2 Swirl".