The line may also be one of the first to be upgraded, alongside the Piccadilly line, with new trains, systems and platform-edge doors to test the systems before the Central and Bakerloo lines are upgraded.
Banen bliver en af de første til at blive opgraderet, sammen med Piccadilly line, med nye tog, systemer og perrondøre, for at teste systemerne før Central og Bakerloo lines bliver opgraderet.