Note: Bank branch trains will not stop at Kennington Station from 26 May until September 2018, due to upgrade work at the station.
Southbound trains on the Charing Cross branch may terminate here. Due to the tunnel arrangement south of the station (the Kennington loop; see diagram), it's much easier to turn a Charing Cross branch train around here than a Bank branch one. (More details at the Wikipedia entry linked below.) Sadly, staying on a terminating train and riding it round the loop is not permitted.