Presumably in an effort to quell commuters' constant rage, New York's Metropolitan Transportation Authority has released a video explaining the science behind delays on the subway - and it's in the style of an 8-bit video game.
So what happens? According to the video, subway (and, presumably, London Underground) trains usually have a regular interval between them, but if there's a problem - such as a passenger being taken ill - the trains behind the affected one will get stuck, while the ones ahead of it keep going, which can eventually cause delays to the entire line.
Instead of letting that happen, the transit authority holds trains at red signals to close the gap between the trains. In New York, that gap can't be more than 25 per cent of the scheduled interval. Meanwhile, Transport for London (TfL) has pledged to reduce delays by 30 per cent from 2011 levels, using measures from increasing the number of rubbish bins (thereby reducing the amount of litter blowing onto the line) to installing high-tech sensors which can work out how many trains are at a junction, and can adjust the length of a green light accordingly.
Still: if Tube delays were always this cute, we probably wouldn't huff and puff so much when we got stuck in a tunnel for hours...