Tech

10 wonderful facts on how the London Underground works

In 2014, the London Underground hosted an average of 26.6 million trips a day.

That's equivalent to the entire population of Mozambique queuing up to take one trip on the subterranean network. Every. Single. Day. 

(Have a good think on that next time you're about to moan about a delay of five minutes on the circle line)

With that number of sweaty bodies to deal with on a daily basis, the minds at Dice - formerly the IT Job Board - got to work investigating the tech that keeps this system ticking along (most of the time).

From escalators to brilliant facts, consider this your pub ammunition for moving the conversation on from unsettling political races.

  • 10 wonderful facts on how the London Underground works

    How an escalator works

    Tube escalators have a pair of chains at their core, looped around two pairs of gears. A 100-horsepower electric motor drives the top gears, which in turn rotates the chain loops; as the chains move, the steps always remain level. The motor also moves the handrail – a rubber conveyor belt configured to move at the same speed as the steps.

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    All the safety kit you'll find in an escalator

    Every single one of the 423 escalators in the Underground has a suppression, communication and fire detection systems built into it, which have to be tested and approved before they can be made available for public use.

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    There's a lot of moving parts in one escalator

    There are approximately 15,000 moving parts in a typical escalator, which is why repairs can take several months to complete.

    All escalators have to be refurbished after 20 years and replaced after 40 years.

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    Great escalator facts

    The longest escalator on the Underground? Angel, measuring 60m long with a vertical rise of 27.5m.

    The shortest? Stratford, coming in at just 4.1m.

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    How an Oyster Card works

    Every Oyster card contains a radio-frequency identification chip (RFID) - effectively a tiny computer.

    When the card is placed near the RFID reader, it creates an electromagnetic field between the two. This allows the data to be transferred to the card identifying the start or end of your journey, and writing data back to the reader. 

    It doesn't actually need its own power source: the reader transmits energy to the card in the form of radio waves, generating just enough power by electromagnetic induction allow the reader to access the card's data. 

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    Every Oyster Card is unique

    Each Oyster card has its own unique number, and that TfL holds journey and transaction data about every Oyster card for up to eight weeks (although full registration details are held centrally, not on individual cards). 

    In addition to helping users track their journey and claim back on trips they've been over charged on, it's also seen Oyster card data used as an investigative tool by the police, who first have to request access from TfL.

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    The numbers are growing

    By 2041, Transport for London predicts that there will be a staggering 32 million trips will be made on the Underground each day. Which is LOADS - 5.5 million more than current figures. 

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    How Wi-Fi works

    Installed as part of measures to help tourists navigate the Underground during the 2012 Olympic Games, there are now public Wi-Fi hotspots at 253 stations. Anyone who has a contract with EE (Orange and T-Mobile), Three, Vodafone, O2 and Virgin can use them.

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    Not really that underground

    Only 45 per cent of the Underground actually exists underground. So they're sort of lying to you...

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    One final fact

    The longest distance between stations? Chesham to Chalfont & Latimer (Metropolitan line) which is 6.3km of uninterrupted track.

    The shortest? At 0.3km, it's Leicester Square to Covent Garden on the Piccadilly line. You might as well walk...