A set of new tunnels being dug between the Bakerloo line platforms at Paddington have been successfully completed despite the challenging conditions they presented.
The new tunnels are needed as they will be used to provide a connection to a new tube station entrance that is being included in the Paddington Cube, a new office block being built next to the mainline station. When it opens, there will be more escalators down to the Bakerloo line, and for the first time, direct lift access. The new entrance may also end up as a shortcut for people on that side of Paddington station to the Elizabeth line thanks to the deep tunnel linking the two lines.
Over the past year, behind hoardings on the Bakerloo line platforms, a new corridor linking the north and southbound platforms has been dug just underneath the existing escalator, and a side passage running between the platforms has been dug to link up with the new station entrance.
All the tunnels were dug using hand-held mechanical diggers, and the soil was stabilised using sprayed concrete linings (SCL), and will later be fitted out for passenger use. According to Bedi Consulting, which was responsible for tunnel engineering consultancy, the project was challenging because of how close the new tunnel was to the bottom of the escalator shaft, and is thought to be the closest underpass of an SCL tunnel to an operational escalator for TfL to date.
They were also allowed soil movements of less than 2mm per metre of tunnel to prevent the escalator above from jamming if its mechanical workings were to slip.
Bedi Consulting said that “for such a small project, it’s been an immense challenge”, especially as the initial plans were to close of the escalator for several months during the closest tunnelling, but they were able to avoid that happening. On top of that, they also came across unexpected piles in the tunnel face when excavating, which needed to be designed around.
The tunnelling was carried out by Tunnelcraft.
When the new entrance opens, there will be a large entrance hall with two sets of escalators down to the ticket hall area, then the new set of double-escalators down to an intermediate floor just above the rail tunnels, then a short staircase down to the platforms. A lift from the new entrance will give step-free access from street to platform.
The design of the new station layout was carried out by Scott Brownrigg.