Overview
- The late‑June weekend of June 26–28 produced peak temperatures around 40 °C and caused network‑wide disruption across U‑bahn, S‑bahn, tram, bus and regional services, the Senate response to Green MPs confirms.
- Heat damaged tram infrastructure on Bernauer Straße and in Köpenick, doubled daily S‑Bahn vehicle faults mainly from electronic door‑control failures, and forced battery‑cooling warnings, locomotive cooling pauses and diesel train breakdowns by mid‑afternoon on regional lines.
- Operators say preemptive maintenance, selective cancellations and passenger messaging limited the worst outcomes but could not prevent notable service loss and discomfort for riders during the heat spike.
- Planned new vehicles are specified to operate up to 45 °C, but onboard climate systems are designed to DIN norms that assume 35 °C and many existing trains and U‑bahn cars will remain without air conditioning until the 2030s.
- Copernicus data show June and July among the hottest on record, the Senate warns repeat 40 °C days are likely, and officials caution that without faster monitoring, retrofits and accelerated procurement Berlin faces repeated summer failures and rising passenger exposure.