The line mainly runs in cut and cover tunnels between West Kensington and Bromley-by-Bow, including the Edgware Road branch. However, due to the nature of sub-surface lines, the cutting is occasionally left open both at and between stations for ventilation. West of Earls Court, the line is entirely surface level, with the exception of the Hammersmith and Fulham Broadway stations, which have been built over by recent developments. There is also a small section of tunnel between Southfields and East Putney.