Much as I love nature and spending time in parks and gardens, I also find heavy industry and construction work aesthetically interesting. Stimulating, even! So one of the highlights of my week was being invited to a viewing of the Tunnel Boring Machines at the Northern Line Extension’s Battersea site, before the TBMs were lowered into the ground to begin their 3.2 kilometre London-clay-eating journey towards Kennington. The Northern Line Extension will see a branch line from Kennington serve two new tube stations, Nine Elms (for the American Embassy) and Battersea Power Station.
A group of interested locals gathered in the site’s first floor Portacabin project office for a short presentation about the tunnelling process, before ascending to the viewing platform to gaze upon these two Things of Beauty. The TBMs have been named Amy and Helen, after Amy Johnson, the first woman to fly solo from Britain to Australia, and Helen Sharman, the first British astronaut in space. Local school children chose the names from a shortlist, and I think it’s great that two pioneering women have been honoured in this way.
How can I explain my excitement? Yes, these are amazing feats of engineering, way beyond my understanding. I like some of the jargon and all those boggling facts. The TBMs will be tunneling at depths of up to 30 metres, and operating non stop with a crew of 35 working in shifts. The clay, apparently, is quite stiff, so will be injected with water and foam to make it more of a porridge consistency. This waste or ‘muck’ is channeled back out the tunnel, onto a conveyor belt that takes it to a barge, and from there to Tilbury to restore arable farmland. As the TBM progresses, carriages are added at the back, so staff continue to enter at the Battersea station box and muck goes out the same way. This is all happening down the road from me! And then look at them. They look like sophisticated space capsules, but also like something you’d find in a Kinder Surprise egg.
A special crane was being assembled as we watched, which can lift up to 750 tonnes. The TBMs weigh 650 tonnes each. Once the TBMs have been lowered into place in the station box (this weekend if all goes well), the crane will be disassembled and removed.
We had a good view down into the station box, where Amy and Helen will begin their underground excavations. The idea that the tube would be extended to Battersea has been around for some time, certainly since 2008. I doubted it would happen. Then, there was talk that it would be completed by 2020, which seemed way off in the future. Now, it looks like it really is going to happen.
The scale of the surrounding development is astonishing. I’ve mentioned before how ambivalent I feel about the rate and extent of change, and the impact on the local community. I still feel this. But there is also part of me that is exhilarated by the activity, and fascinated by the beauty of those cranes and their ever-changing angles; the magnificence of the Power Station; and the contrasting colours and Lego-writ-large aspect of the construction site. Now, excuse me while I write an ode to Amy and Helen.