PC&A has designed and built several dozen railway underpasses, including in many cases the design of the constructive solution that allows the track to be kept in service during the construction of the works.

The projected works are distributed along the various lines that cross the country:
Minho Line (19), Northern Line (10), Beira Alta Line (8), Beira Baixa Line (4), West Line (3), Tomar Branch Line (2), Southern Line (2) , Alentejo Line (2), Évora Line (1), Algarve Line (1).

Here are just a few representative examples of the different construction processes adopted:

- PIR at km 148+911 of the Beira Baixa Line - work of three spans (11.8+19.9+11.8 m) with prestressed reinforced concrete deck, built by the  "top-down" system.  The work began with the diversion of the railway, followed by the driving of piles, concreting and prestressing of the deck, replacement of the track and subsequent excavation under the deck to continue the road trench. (Project: 2010; Client: OPWAY)

- PI at km 79 558 of the North Line, between Santarém and Vale Figueira – 12.0 m wide deck, in double lane, 5.0 m clear span, built by the process of  hydraulic thrust driving. (Project: 2003; Client: Construtora do Lena)

- Pi at km 35 136 of the Minho Line – deck with a width of 12.0 m and 9.5 m of free span was carried out in two phases, always keeping one track in service, through a process of  provisional containment  in a first phase and  armed landfills  with geogrids in the second phase. (Project: 2000; Client: REFER)

- PI at km 169 671 of the Northern Line – located at Pombal Station, it allows pedestrian access between the various platforms of the Station. The underpass has a total length of 57.0 m and a clearance of 6.0 m. Access is via stairs, two elevators and ramps with about 150 m of development. It was built through  lane suspension  with several containment fronts. (Project: 1999; Client: REFER)