Goggle screens are decribed as being basic TV screen that are used on the more technologically advanced Traction City. They were first mentioned in Mortal Engines when London is huntingSalth
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An image of what a goggle screen might look like

ook. The cameras on the bottom decks captured images of the town while london was chasing Salthook. The images were then veiwed by people on the top decks. The Goggle Screens also must have speakers because information about Salthook could be heard.