# Warsaw M4 metro line development

> Live situation record from CLSTR: https://clstr.news/situations/warsaw-m4-metro-line-development
> Updated: 2026-08-14T11:01:39.000Z. Sources: 2. Developments: 2.

Warsaw has initiated geological investigations for the development of the M4 metro line. In the Białołęka district, drilling teams have begun using rigs and ground-probing sondes to create boreholes reaching depths of up to 52 meters. This phase of investigations, which includes hundreds of drillings and various geophysical tests, is intended to help select construction technologies and ensure safety, with completion expected by autumn 2027.

The proposed M4 line is envisioned as a 26-kilometer route featuring 23 stations that would connect nine districts, spanning from Białołęka to Wilanów. The project is expected to include two transfer points to the M2 and M3 lines and may feature driverless operation. A conceptual design for the entire line is slated for completion by November 2027.

## Timeline

### 2026-08-14: Warsaw plans M4 metro line to connect nine districts

Warsaw plans to develop the M4 metro line, a 26-kilometer route connecting nine districts, with a conceptual design expected by November 2027.

2 sources. https://clstr.news/cluster/warsaw-plans-m4-metro-line-to-connect-nine-districts

### 2026-07-21: Warsaw begins extensive geological drilling for new M4 metro line

Warsaw starts deep geological drilling in Białołęka for the upcoming M4 metro line, aiming to complete over 900 boreholes and related studies by autumn 2027.

2 sources. https://clstr.news/cluster/warsaw-begins-extensive-geological-drilling-for-new-m4-metro-line

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Cite as: Warsaw M4 metro line development. CLSTR, https://clstr.news/situations/warsaw-m4-metro-line-development