Consulting engineer WSP has analysed all the rail tracks in Transport for London’s (TfL) fare zones 1-6. It identified where there were no breaks in the track made by tunnels, roads or bridges and where there was 10 metres of available land on both sides.
Its report, Out of Thin Air, says there is the potential to provide all the new homes London needs if existing engineering techniques were used to construct apartment blocks directly above these lines.
This would allow for the development of 100m² apartments in buildings rising to 12 storeys. If just 10% of this total was delivered, it would provide 250,969 new homes.
The London boroughs of Brent, Ealing and Croydon and TfL Zones 2, 3 and 4 provided the most ‘overbuild’ development potential, the report says.
Rail overbuild could also help connect communities divided by the tracks, it suggests.
WSP director Bill Price said: “We have to be more creative in using existing space in what remains a relatively low-rise city. The air rights above rail tracks present an unrealised but significant opportunity to build more new homes on brownfield land. It’s important to emphasise the engineering is absolutely possible and not new. We have been working on projects of this nature in New York for decades. Right now in London we are working on a variety of projects that rise above rail lines including a 50-storey residential tower, homes above a new Crossrail station and even a Premier League stadium.”
“There is a wider point about how we can better connect communities and unlock new homes not just above rail lines but adjacent to them as well. In some parts of London rail lines act as accidental segregators. By ‘decking’ over these lines, such as the proposed regeneration west of Earls Court underground station, we can join together sites to unlock an even higher number of new homes and create new vibrant communities.”
The thinking behind the report emerged after Network Rail appointed WSP in 2012 to study the feasibility of building above rail lines. The study’s conclusions, which focused on the type of decking and noise and vibration issues are detailed in the new report. CGI designs are also provided of what rail overbuild might look like if implemented near a major rail terminal in Central London, above a rail line in West London, and above a station in North London.”
A previous WSP report focused on general ‘overbuild’ involving better land utilisation by creating new residential accommodation above existing public buildings such as hospitals.
Pictured below are the rail tracks leading to/from Victoria Station, and how they might look if built over. The images are from WSP's report.