There were severe delays on the Piccadilly Line, including on trains to Heathrow Airport, at lunch time on Friday due to a signal failure at Caledonian Road.
Earlier on Friday the Metropolitan Line was part-suspended due to flooding as heavy rains fall across London, with no trains running between Chalfont & Latimer and Chesham.
Commuters also faced severe delays at rush hour on Friday morning on the Overground and District Line due to track faults at Kew Gardens and Clapham Junction.
