Because all of the posters plastered on every single surface on the inside of the cars is clearly not enough advertising for your average subway passenger, London is poised to light up a half-kilometer-long LED display in the tunnel between Heathrow and Paddington Station. Manufactured by Canadian firm SideTrack, the simulated video system -- which is composed of 360 individual LED bars synchronized to train speeds -- will replace a static version already installed along the same Heathrow Express route, thus allowing officials to change the message without swapping out physical signage. No word yet on who the premiere advertiser will be, but this medium would seem like a good way for rental car companies to make a compelling point: "Avoid these crappy ads, rent from Avis next time."

[Thanks, Jamie D.]

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