You may already have noticed changes to the Metropolitan line, where our upgrade involves new trains, tracks and signalling.
We've introduced a brand new fleet of fully air-conditioned trains to the line, the first in 50 years.
They have more spacious walk-through carriages and, to help you during your journey, the trains are fitted with visual displays and feature automated station announcements. There's also the reassurance of CCTV.
A signalling upgrade is underway on the Metropolitan, Circle, Hammersmith & City and District lines, which together make up 40 per cent of our network. This will allow us to run more trains, more often and more reliably. Combined with bigger trains that we can move more quickly and closer together, it'll mean more room - or capacity - on the lines.
When the upgrade is complete the combined line capacity will increase by 65 per cent, which means we can carry about 17,000 more passengers an hour.
Kings Cross St. Pancras
In 2010, we completed a massive redevelopment of King's Cross St. Pancras that quadrupled the size of this key station.
It already sees more passengers a year than Heathrow Airport, with more than 100,000 people passing through the station at peak times every day.
King's Cross St. Pancras is now modern and spacious, has step-free access to all lines, and is less congested thanks to new ways to enter and exit the station.