Kennington Loop
A loop tunnel south of the station enables southbound Charing Cross branch trains to be terminated at Kennington, leave the station in a southward direction and, traversing the loop, enter the northbound Charing Cross branch platform. Because of the arrangement of junctions, trains using the loop cannot reach the northbound Bank branch platform nor can trains from the southbound Bank branch reach the loop. For southbound Charing Cross branch or Bank branch trains to reach the northbound Bank branch platform a reversing siding between the two running tunnels must be used.
Because of the layout, it is almost always southbound Charing Cross branch trains that terminate at Kennington. One of the station's four platforms is thus mainly used by terminating trains and sees relatively few operational departures.
The loop tunnel is said to be haunted. There have been several reports, by train drivers, of hearing the doors between the carriages being opened and closed in sequence, as if someone (or something) is walking through from the back of the train to the front, where the driver is. Kennington park, above the loop, was historically notorious as a place of execution; St. Marks Church, near the southern end of the loop, was deliberately built on the site of one of the main gallows.
Read more about this topic: Kennington Tube Station