District line
Originally, the station had an island platform with District line trains serving one side in each direction. However, with the introduction of the Piccadilly line tracks, the eastbound District line track became the westbound Piccadilly line track and a new platform was built for the eastbound District line. This is why there is one island platform and one side platform serving three tracks; the eastbound Piccadilly line track is the only track that is unable to serve the station.