The estimated municipal investment is €120 million including VAT. Of that sum, €65.5 million is for enlarging and duplicating the Diagonal rainwater collector, while €54.5 million will fund redevelopment of the avenue. The Autoritat del Transport Metropolità (ATM) is expected to contribute approximately €97 million, financed by the Generalitat de Catalunya, for the tramway infrastructure and rolling-stock-related works. On these reported figures, the combined investment is approximately €217 million.
Barcelona d’Infraestructures Municipals (BIMSA) launched the tender on 2 November 2026 for the second major phase of the tram connection. The works will extend the route along the Diagonal between Verdaguer and Francesc Macià, closing the central gap between the eastern Trambesòs and western Trambaix networks. This phase follows the earlier extension linking Glòries and Verdaguer. The tender is divided into five lots. They cover tramway infrastructure and collector works, with public-space redevelopment also included.
The collector works continue the intervention carried out during the first phase. They are intended to increase hydraulic capacity by up to 60% during torrential-rain episodes. That would improve drainage along the Diagonal. The city’s €65.5 million allocation for the collector is the largest single component of its contribution. Deputy mayor Laia Bonet said the works would allow the city to double its hydraulic capacity at a key point.
Once connected, the Trambaix and Trambesòs networks would provide a continuous east-west link between municipalities in the Baix Llobregat and the Besòs corridor through central Barcelona. The journey between Campus Diagonal-Besòs and Zona Universitària is expected to take less than 40 minutes. The project pairs the tram connection with redevelopment of the avenue. It also includes improvements to underground rainwater infrastructure. Barcelona’s broader municipal agenda has also featured in Barcelona city coverage.
Barcelona and the ATM aim to select contractors in spring 2027, with construction expected to begin in summer 2027. The works are estimated to take 40 months. The project plan calls for traffic to remain in circulation during construction. After construction, the line must undergo testing and trial running without passengers before entering service, which is planned for 2031.
