Half the LU tunnels are barely larger than the train, the other half are cut'n'cover. And they're rarely straight. And most lines run from 5am to midnight. S

Half the LU tunnels are barely larger than the train, the other half are cut'n'cover. And they're rarely straight. And most lines run from 5am to midnight. Some now run almost 24 hrs. That probably influences the decisions on roll-out and cost. TFL has been ahead-of-the-curve with the rollout of some tech (Oyster cards, tap'n'go), but not so much with others when they get hacked. https://www.bbc.co.uk/news/articles/c4gqg2elkj4o https://www.bbc.co.uk/news/articles/c4gqg2elkj4o https://en.wikipedia.org/wiki/Oyster_card#Precursor https://en.wikipedia.org/wiki/Oyster_card#Precursor