The Bakerloo line as a case study in technical debt

The oldest deep tube line in the world is a brilliant illustration of what happens when you can’t take a service down for a refactor. The trains are from the seventies. The signalling is older than I am. And yet a million journeys a week happen on it without anyone really noticing.

A piece on what “legacy” actually means when the legacy is also the load-bearing wall of a city.