There is a substation at the east-end of Shepherd’s Bush Market station. The gap allows for sections to be switched on/off in turn rather than all at once. Sectionalisation across the network allows faults to be detected and isolated much easier. On that Line, gaps are at Shepherd’s Bush Market, Royal Oak, Bouverie Place (Praed Street junction), Baker Street, Chalton Street (King’s Cross), Farringdon, Moorgate, Whitechapel, Campbell Road, West Ham, Plaistow, East Ham.
At the section gap, facing the driver would be a Rail Gap Indicator, consisting of a triangular set of three red lights on a white background, colloquially known as “cherries”.
Last Edit: Apr 14, 2023 10:38:48 GMT by Dstock7080
Apologies, i've just re-read your original post describing gaps at west-end - my reply was based on those at the east-end. These small gaps with cabling running around them are for sleet/snow clearance, a build-up of sleet/snow ahead of the shoe would drop down.