Access
Back in the 80s when I was in this business (planning the BT digital trunk network) I was occasionally asked why we didn't use underground rail tunnels for routing cables in view of the obvious attractions. The problem comes with getting access to faulty cables while bloody great trains keep whizzing through the tunnels for upwards of 18 hours a day. "Sorry, can you suspend the Northern Line while we fix this problem please".
I expect much the same of sewage tunnels except with fewer trains and more added dampness plus piles of ordure. Then there are the aforementioned Fatbergs to consider. Much of the problem with London's sewers comes from having a combined rainwater and foul water system. Indeed, the whole system is designed to use the rainwater to push the lumps through to the collection stations. When there is a major rainfall, there can be overflow into the Thames. If you view the Embankment wall at low tide you can see large cast steel shutters which excess water force open. This is what caused much of the more recent pollution to the river. Much work has been done to stop this but the problem of access to cables in sewers remains.
Splicing fibre cables while up to my waste in London's finest is not a job I fancy.
Biting the hand that feeds IT
