TBM Charlotte has bored a 1.1km connection tunnel that will take sewage overflows from King George’s Park into the main 25km tunnel at Carnwath Road, where it will be transferred to east London for treatment instead of polluting London's waterway.
The 30-metre-deep Frogmore connection tunnel is part of the western section of the project, being built by a joint venture of BAM Nuttall, Morgan Sindall and Balfour Beatty.
Charlotte is one of the Thames Tideway project’s smaller TBMs, measuring three metres wide and more than 70 metres long, and is named after suffragist Charlotte Despard. She was the first to break through the ground to complete a section of tunnel for London’s new super sewer in October 2019.
Having dug the 500-metre southern section of the Frogmore connection tunnel, from Dormay Street to King George’s Park, she was then hoisted from the shaft, taken back to Dormay Street and put back into the ground to tunnel the final 600-metres in the other direction to Carnwarth Road.
Ciaran McQuaid, shafts and tunnels project manager for the western section of the project, said: “It’s amazing to see Charlotte finally through into the Carnwath Road reception chamber and a big congratulations to the team for all their hard work. This will probably be the end of my 12 year connection with TBM Charlotte from being a shift engineer on her back in 2008 on the Thames Water ring main extension, watching her going through her remanufacturing ready for tunnelling on Frogmore connection tunnel and then completing her job in style. For a TBM that is turning 26 in November and has now completed six tunnel projects, she did a great job.”