...always annoys me that this board's software doesn't recognise the home nations' TLDs.

Anyway, this thread's book recommendation is The Subterranean Railway, by Christian Wolmar. Much like the author's other work, this is a social history, rather than lists of dates and engineering specifications - this time of how the London Underground came about in the first place, developed under a succession of geniuses and dodgy characters, declined post-WW2 into the 1950s, and somehow stuck around from Eden to Thatcher to become one of the world's finest urban transit networks.

As you'd expect, other than the stuff everyone knows already (London clay! Metro-land! Harry Beck's Tube map! Everyone's favourite anti-hero, Charles Tyson Bloody Yerkes!), the entertaining stuff is the shit that was flung at the wall that didn't quite stick - or how they actually got permission and funding before spades hit dirt - or how some things (NIMBYism, constant rows over financing and construction) truly never change. It's good. Go read it.