The replacement of four steel segments near the municipalities of Granollers and Massanet was included in the operations performed for the comprehensive renovation of the railway line running through Tarragona, Barcelona and France. The aim of this replacement was twofold: besides solving problems detected on structures over 50 years old, the project was also focused on converting a track fixed directly to a bridge deck into a structure on ballast. Doing so improves maintenance and operation of this busy freight and passenger transportation rail line. Due to strict operating limits, the construction challenge was that bridges had to be replaced in one night. During the 8 hours in which works were executed, catenaries and the existing bridge had to be dismantled, the new deck and track superstructure were erected and electrictraction equipment was restored.

The first bridge, located in K.P. 148+990 of the line running through Vilanova stream, was replaced by a 30 m single span double bridge. U section had a total depth of 2.75m and the length of each section was 4.820m. The second and third structures (also known as ‘Mogent bridges’), located in K.P. 149+400 and 149+924, were replaced by 2 double bridges of 36.50m span. The first of them has a depth of 3.35m a span of 22m. The depth of the second bridge is 2.20m. Both bridges have a U section and the first of them is extremely skewed, which made positioning and final installation more complicated. The last bridge, located in K.P. 165+340 over Repiaix stream, was replaced by a 31m span single truss Warren bridge with spandrel columns. The total depth of the structure is 5m and it has a width of 9.60m.

In total, all four structures are composed of 520 kg/m² steel, 65% of which corresponds to the cross-sectional structure and 35% to the orthotropic slab.