Transport · Railway / metro
Four Lines Modernisation
TfL’s Four Lines Modernisation programme replaces trains and signalling across four Underground lines. The remaining programme principally concerns Metropolitan line signalling and software.[1]
Current position
Delivery delayed: SMA13 has moved from H2 2027 to H1 2028; programme close-out is forecast for 2029.
TfL’s October paper forecasts SMA13 commissioning in H1 2028, SMA14 in H2 2028, then close-out in 2029.
Delivered and outstanding
- Delivered: new signalling served 70 stations and four junctions by August 2026. SMA10 and SMA12 commissioned the planned District line sections.
- Outstanding: Harrow and the northern Metropolitan branches require further commissioning, software development and testing.
Timeline
2016
New S Stock fleet fully introduced.
June 2025
SMA8 commissioned.
August 2026
SMA10 and SMA12 commissioned.