In 2013, workers performed a famous feat of engineering at a big Tokyo train station. Transit authorities were converting a surface rail line to a subway, which meant lowering one set of tracks to connect with another, underground set. To avoid inconveniencing commuters and disrupting Tokyo’s vast and heavily travelled transit network, they decided to execute the final step of the delicate operation in the four hours between the departure of the last train from the station and the arrival of the first train the next morning.
