Possible Clues:

• Aerodynamic ridge
• Street scratcher on a wheel
• Hull may have this street with dissolute character
• Line of planking in the hull of a wooden ship
• Street scraper on the wheel
• On the wheel it scrapes along at the end of the street
• The street gets a scrape from a bit of the wheel
• Will this scrape the street with a bit of the wheel?
• The street might scratch that bit of the wheel
• Line of planks in slope at end of street