We need a long term plan for the Brighton Main Line

5 April, 2017

The long-awaited Department for Transport report into the future of the Brighton Mainline was finally published last month (ref 1). It rules out the idea of a new relief route – ‘BML2’.

Dated April 2016, long-suffering commuters may well conclude that a good deal of water has passed under the Balcombe Viaduct in the meantime.

The report addresses:

  • Network Rail’s planned upgrade package for the mainline
  • opportunities that re-opening Lewes-Uckfield and other missing links might offer for local connectivity and for an alternate ‘relief’ route north
  • the long-term potential of new, higher-speed opportunities for rail between London, Gatwick and Brighton.

The fundamental conclusion of the study, carried out for DfT by WSP, is that Network Rail’s upgrade plan for the Brighton Mainline should proceed without delay. In CP6 (2019-24) this focusses on relieving infrastructure bottlenecks in the Croydon area through grade separation of 3 key junctions and an additional 2 platforms at East Croydon. This would unlock an additional 2 tph into both London Bridge and Victoria.

Other constraints remain. Longer term, as yet uncosted rebuilds of Clapham Junction and Victoria would be more challenging to achieve, certainly whilst keeping these incredibly busy stations running during construction. How could these be achieved if some kind of alternative was not already in place? Incrementalism has its limits, perhaps.

The WSP work briefly considers proposals put forward by stakeholders for a new, high speed line that could reduce journey time between London and Brighton to less than 30 minutes, including a stop at Gatwick. This would have the advantage of bypassing the infrastructure constraints ‘down’ the line, namely the Balcombe and Clayton tunnels and the Grade 2* listed Balcombe Viaduct. WSP have little information on which to reach a firm conclusion on this suggestion. In particular, they make the assumption that the propensity to commute essentially remains fixed, as “both lines (would) compete for the same pool of commuters that were previously using the BML” (ref 2).

One flaw in investigating long-term rail investment options is the DfT’s cap on passenger growth assumptions beyond 20 years hence. This is standard protocol in managing forecasting uncertainty, but makes it very difficult to compare long-term options with different capacity objectives.

Some strategic thinking is needed here.

The long-term market for travel on the BML could respond very positively to a step change in connectivity that a new, high-speed line would unlock. For example, there is already evidence that Brighton acts as a satellite to the high-tech digital cluster around Farringdon/Old Street, in part due to the direct rail connection that exists. The agglomeration benefits of a much better link could be significant, and fit well with strategic economic policy and the productivity growth agenda. Furthermore, the traditional market segmentation between daily commuting and business travel is blurring, as the world of work evolves. This may encourage higher growth for more longer-distance travel to match high-worth work opportunities with high-value residential environments, such as Brighton and Hove. Although WSP considers housing growth projections as a basis for growth, what they fail to take into account is the change in propensity to use rail if service quality is transformed.

Connectivity gains alone are unlikely to justify a new fast line alone. What might do is the creation of a much higher capacity South London metro operation on existing lines (possibly based on high levels of automation (after all it’s been done with the DLR)). A new tunnelled higher-speed route could allow this to happen, and to avoid expensive central London terminal costs it could be cross-linked with an equivalent northside route. It’s too late for HS2, but this could be very relevant for future development, giving both north (say Stansted/Cambridge) access and south access to central London and/or Canary Wharf.  Such concepts lie beyond the confines of individual route-based studies but they should not be ignored.

So yes, let’s press ahead with immediate improvements to the Brighton Mainline. But let’s not rule out more radical, higher speed options in the longer term. There may be very good strategic capacity and economic connectivity gains to be had.

Ref 1 – London & South Coast Rail Corridor Study. Department for Transport WSP/PB. April 2016.

Ref 2 – Op. cit section 7.3 p50.