Alex Bell Profile picture
QI Elf occasionally on @nosuchthing and @bbcradio2 🔍🏳️‍🌈

Jan 19, 2020, 20 tweets

it takes Tower Bridge 90 seconds to get fully erect, to 87 degrees

the record is 64 times in one day

but it doesn’t get it up as much as it used to :(

MORE TOWER BRIDGE FACTS

the bastules only open as much as is needed to let each boat through, to preserve the mechanisms

except for when the Queen sails through, it always opens up fully because she is a 𝒸𝓁𝒶𝓈𝓈𝓎 𝓁𝒶𝒹𝓎 and needs her space

Tower Bridge is insured by Lloyds of London

it’s technically classified as a ship because that’s the closest thing they could compare it to

these blue lads are probably the result of a design mistake - when the bridge is down, the curved lifting mechanism sticks out through the wall a bit so they just built some little wooden covers around them

#sloppy

more #bastulechamber fun: I was always told as a kid you’d get crushed to death if you got stuck in the room when the bridge lifted and the counterweight swung down

disappointingly it seems there are buffers and a couple of feet of space between the weight and the wall

CONTROL ROOM

no facts here just pretty engineering

ps this is George one of the 6 engineer qualified to drive the bridge

yet again i was not allowed to try and asked to stand at the back away from the working equipment

this is the old steam-powered lifting engine, and you can see the bit where they cut the driveshaft off - to replace with this shiny new but less pretty electric engine

also I forgot to take pictures but there are just massive fuckin spanners EVERYWHERE

the engineers use them as doorstops and paperweights and probably toothpicks it’s metal as hell

THIS is cool - traffic constantly driving over the bridge would put too much stress on the axles that the tilts bits sit on - so the engineers designed hydraulics to lift the weight of the road off it when the bridge is down

[this is not it, these are just more cool pics]

aaand upstairs! aka prostitute central walkway

and you can put one foot in north London and one foot south

misc

AND you get a badge for being brave enough to stand on the glass floor

(which I did before I even knew there was a sticker up for grabs so guess that makes me doubly brave idk no big deal whatever 🤷🏼‍♂️)

facts i havent checked yet but huge if true:

a haybale is hung from the bridge to notify boats if the clearance height has changed eg scaffolding

in WWII a bomb bounced off the bridge and hit a boat

4 of the 6 recent bridge failures were due to the switch from Windows XP to 7

also that glass floor has shattered like FIVE TIMES from people dropping bottles and phones on in

that does NOT sound safe

here’s that bascule chamber vid again in the thread because it’s SO COOL

ps. those wall grooves have no part in bridge movement, they were used for construction only

here’s an alternative proposed drawbridge design

ok the riveting - obviously no 1880s health and safety...

metalworkers would heat the rivets on the floor and then THROW THEM UP WHILE THEY WERE MOLTEN to the riveters on the steelwork who would CATCH THEM IN A GLOVE or bucket

i mean honestly

in a 24 hour day that’s basically 10 minutes bridge down between each lift (which take 10-12 mins to complete)

*basCULES sorry autocorrect

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