The Euston Rd was built in the fields that lay to the north of London allowing users to avoid the city itself. The road was built to drive sheep and cattle to the markets in Smithfield and for the army to be able to quickly enter or exit the town. Sheep are now seldom seen on the Euston Rd.
Perhaps a portion of the juggernauts clattering through the canyon contain the frozen carcasses of livestock that are still making their way to Smithfields.