The Minister for Development, Magdalena Álvárez, visited the site of the new suburban railway station in the Puerta del Sol, Madrid on 29 May.

The station is being built by FCC Construcción for a budget of €140 million.

The new suburban station, still being built, will connect Atocha and Chamartín through a single tunnel 8,500 m long and will provide direct access to the city centre without the need for changing trains for the two suburban lines that currently terminate in Atocha, the C-3 (Aranjuez) and C-4 (Parla) as well as increasing connections with the Metro.

The Puerta de Sol station, in the square with the same name, has two main parts: the platforms tunnel and the access vestibule with connections to the Metro.

The vestibule is being built from the surface with screens with intermediate floors. The tunnel, unique in the world due to its properties (207 metres long, over 20 m wide and 15 m high) has been designed as a space with two levels, the lower one for the platforms and the upper one for passenger movement. Currently, work is finishing on the tunnels connecting with Metro lines 1, 2 and 3, which also pass through Sol.

The safety measures adopted during the building have been one of the aspects causing the greatest interest. The ground has been pre-treated from the shafts and galleries with consolidation injections, the filling of hollows, compensation, reinforcement and improvement, to ensure the full protection of the buildings and structures over the tunnel. These measures have protected an area of 1.5 hectares with a total length of injections of over 15 km.

The results of these treatments on the surface and in the structures has been tracked with 400 control elements from which data are read several times daily and analysed. This instrumentation was complemented with computer modelling before building work started on the tunnel, including the reinforcement with injections and their possible effects on the surface. The excellent results have shown the suitability of the building system and the effectiveness of the protection treatment.