A CAR struck the viaduct over Northolt Road by South Harrow Tube station, causing Tube bosses to suspend the Piccadilly line temporarily.
The vehicle collided with the bridge at around 4pm but is not longer on the scene. The line has reopened but is experiencing minor delays.
A spokeswoman for Transport for London said: "It seems like cosmetic damage. The line would have been suspended as a precaution to allow engineers to inspect the bridge to ensure it was structurally sound before resuming services."