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A train-sized tunnel is now carrying electricity under South London Published on 16th December 2025 by Ian Mansfield in London News Electricity has started flowing through a deep-level tube train sized tunnel running through South London. [National-Grid-London-Power-Tunnels-2-map-1024x644]New power cables map (c) National Rail The first of two new circuits that connect National Grid's New Cross substation in Southwark with its Hurst substation in Bexley is now live, running for 18km beneath South London through tunnels up to 50 metres deep. This new link replaces one of two buried cables that have served the capital since the 1960s, with the other to be replaced when the second New Cross-Hurst circuit goes live in the new year. While the old cables were buried in shallower trenches in the streets, the LPT2 network carries power in three metre wide tunnels deep beneath the road network. In total, the PS1 billion London Power Tunnels 2 (LPT2) project, which began in 2019, spans 32.5km across seven South London boroughs from Wimbledon to Hurst. Construction of the tunnels began in March 2020, and tunnelling was carried out in three sections between existing National Grid substations: * Wimbledon-New Cross (12km) * New Cross-Hurst (18km) * Hurst-Crayford (2.5km) [svg][National-Grid-London-Power-Tunnels-2_cropped-1024x569]National Grid - London Power Tunnels 2 The current London Power Tunnels project through South London follows the completion in 2018 of the first phase - a seven-year, PS1 billion project to construct 32km of tunnels and two new substations to rewire the network in North London. Tagged with national grid [INS::INS] SUPPORT THIS WEBSITE This website has been running now for over a decade, and while advertising revenue contributes to funding the website, it doesn't cover the costs. That is why I have set up a facility with DonorBox where you can contribute to the costs of the website and time invested in writing and research for the news articles. It's very similar to the way The Guardian and many smaller websites are now seeking to generate an income in the face of rising costs and declining advertising. Whether it's a one-off donation or a regular giver, every additional support goes a long way to covering the running costs of this website, and keeping you regularly topped up doses of Londony news and facts. If you like what you read on here, then please support the website here. Thank you 11 Comments on "A train-sized tunnel is now carrying electricity under South London" 1. Terry smith says: December 16, 2025 at 3:37 pm Hi Ian visits.co.uk great report above Much needed power upgrade with so much more housing construction / tower blocks and ev vehicle charge points Fast food restaurants I'm surprised network is still working . Reply + Alistair twin says: December 16, 2025 at 11:22 pm Electricity usage has actually been declining since 2005, thanks to more efficient appliances, lighting etc. https://www.researchgate.net/figure/ Graph-showing-UK-electricity-demand-in-TWh-over-time-Note-the-peak-demand-was-around_fig2_351872522 This is migh change as we shift to EVs and Heatpumps but efficiency gains will continue and we have a fair bit of headroom to play with as these are not generally peak-time intensive 2. Ian Bouglas says: December 16, 2025 at 5:27 pm How come this project can be completed without fuss or drama but similar railway related projects lurch from crisis to crisis, blowing budgets and missing deadlines. Reply + ianVisits says: December 16, 2025 at 5:29 pm Because even for rail projects, digging the tunnel is the smallest and easiest part of the job. It's the stations, trains, tracks, signalling, fire safety, ventilations, emergency facilities, etc that blows the budget. + MITCHR says: December 16, 2025 at 10:54 pm Title is slightly misleading, it says train sized tunnel, if you look at stock image the whole diameter is a train, to fit a train would be considerably wider = I expect exponentially. Plus rail normally requires 2x tunnels for different directions. + ianVisits says: December 17, 2025 at 8:18 am It's only marginally smaller than a tube train tunnel. 3. Richard says: December 16, 2025 at 5:28 pm The fact is that this power upgrade project was started at least 25 years ago ! I remember that when I lived in Lambeth a quarter of a century ago, I was sent a letter informing me that the tunnel would be passing under my house, requesting information on any wells etc. They then sunk a borehole in the road outside, capped with a small steel cover, which is probably still there to this day. Infrastructure projects in this country move at glacial pace ! Reply + Rtt says: December 16, 2025 at 6:07 pm Not just in the UK. California High Speed Rail, Berlin Airport, ghost airports in Spain, the endless plans for a rail or metro link to Dublin Airport, high speed rail between Lisbon and Madrid, etc, etc. 4. Peps says: December 18, 2025 at 7:39 am The image with workmen accessing the length of the tunnel using bikes is worth a comment! Reply + harry says: December 18, 2025 at 8:54 am But there needs to be another 49 bikes before they get the required *fifty* cycles 5. rjp says: December 20, 2025 at 1:47 pm Is the New Cross substation actually in Southwark? The map shows it in Lewisham (eyeballing it - somewhere vertically centred between Lewisham and Greenwich DLRs) - I can't find anything useful in a search about its actual location (just something about vertical boreholes on Old Kent Road - nowhere near the location on the National Grid map.) 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