The full story of how a short section of the Northern Line underground rail tunnels in London were finally made resistant to sulphuric acid attack appears in the latest issue (vol 153 no 1) of the ICE Transport journal. The acid, created by groundwater and tunnel air reacting with iron pyrites, has been attacking the tunnel near Old Street station for more than 50 years.
Summaries of all papers can be read at www. transport-ice. com.