Trento Railway Bypass
Design, coordination, and sustainability of a complex infrastructure
As part of the Project for the construction of Lot 3A of the Quadrupling of the “Fortezza-Verona” railway line – Lot 3A: Trento Bypass” for Rete Ferroviaria Italiana (FS Group), NET is responsible for the Detailed Design, Detailed Executive Design and As-Built documentation for the construction of the hydraulic works and environmental studies, as well as for drafting the preliminary documentation for the management of waste materials and excavated soil and rock for the entire project.
The works, commissioned by RFI to the Tridentum Consortium of Companies (Webuild, Ghella, Seli Overseas, Collini Lavori), involve approximately 13 kilometres of new railway line which, starting from the historic line at Mattarello, bypasses the city of Trento before rejoining the existing railway line in the north of the city.
The new line, almost entirely underground in tunnel, requires the construction of new railway works at the portals in two very different contexts, both dictated by very specific design requirements and considerations: on the one hand, to the south, in the Mattarello area at Acquaviva, characterised by significant naturalistic value due to the presence of watercourses including the Rio Scanuppia and the
Fossa Maestra di Mattarello, several active springs and a cultural heritage asset protected under the Code of Cultural Heritage and Landscape; on the other hand, to the north, set within a densely built-up area with very limited space for construction sites, significant traffic flows, and where the alignment itself runs alongside contaminated areas identified as Sites of National Interest.
Since the project’s start in March 2023, NET has been responsible for the hydraulic studies and the design of works to resolve hydraulic interferences with the new railway alignment, as well as the drainage systems for the railway line, technological yards and associated road networks.
In the environmental field, NET is the designer of the environmental studies aimed at analysing the impacts of the operational line on noise, vibration and landscape, identifying the necessary mitigation works with reference to current sustainability principles as required by the applicability of the CAM (Minimum Environmental Criteria), the DNSH (Do No Significant Harm) guidelines and the Envision protocol.
NET is also responsible for the Environmental Construction Site Project, i.e. the set of analyses (also carried out through predictive modelling) and the identification of mitigation measures for the impacts caused by the construction sites including operational construction sites, storage areas, the base camp and technical areas — as well as the impacts generated by construction vehicle traffic on city traffic.
As environmental designer, NET has developed the documentation relating to the management of excavated materials and excavated soil and rock, in addition to all the in-depth studies that were needed from the outset regarding the interference of the new works with areas characterised by previously known contamination (SIN), and the potential impacts that the project would have caused in this context.
This was carried out through the drafting of Environmental Investigation Plans, subsurface pollutant dispersion modelling, and documentation supporting the administrative procedures for resolving these interferences. Moreover, during the initial characterisation activities, new evidence of contamination emerged, making it necessary to update the environmental
reference framework and identify further specific measures for the construction of the works. In this context, NET has proven to be a fundamental and constant presence for technical and regulatory assessments, drafting documents pursuant to Art. 242-ter (of Legislative Decree 152/2006) for the analysis of interference with contaminated sites, site-specific risk analyses, technical notes and documentation supporting assessments carried out with the relevant regulatory authorities, as well as with the Contracting Authority and the contractor.
NET also provides assistance and support with regard to noise analysis, intervening whenever changes to the construction site layout or variations in the operational methods adopted for carrying out the works become necessary.
From a hydraulic standpoint, the project involves the adaptation of several watercourses affected by interference, both in urban areas and in the valley in the south of the city.
Indeed, in this area, in addition to the railway works at the outlet of the main tunnel, a major construction site area is planned adjacent to the Rio Scanuppia.
NET therefore carried out the studies aimed at identifying the channel realignment and hydraulic engineering works, both in the final configuration and in the temporary configuration — the latter in turn comprising several sub-phases according to construction needs — with the goal of ensuring the safety of the territory while minimising the repercussions that the construction site itself could cause during the transitional phase.
In coordination with the relevant authority, temporary hydraulic protection works were also designed with regard to residual hydraulic risk for exceptional return-period events (100–200 years).
Hydrological analysis, hydraulic compatibility studies and two-dimensional hydraulic modelling were then carried out to define the interventions, which today have already been partly completed on site.
In the north, for the Malvasia Canal, the Roggia degli Armanelli and the Lavisotto Canal, interventions were developed to make the watercourses compatible with the planned railway works.
