# BIM and Digital Twin for transport infrastructure: bridges, railways and stations

> How BIM and Digital Twin support bridges, railways and metro stations from tender to site, with BIMON's work on Skurusund, Naples-Bari, Doha and Afragola.

Published 2025-06-04

On bridges, railways and metro lines, BIM puts every structure of the route in one coordinated model linked to quantities, schedule and cost, so that the contractor can price, plan and build with fewer surprises. The digital twin extends that model into operation, where inspection and maintenance data are attached to the same objects.
Transport infrastructure has two features that make digital methods especially useful. It is linear, so the same types of structure repeat over kilometres. And it is built in the middle of existing networks, so interference with roads, railways and utilities drives cost and time. This article looks at four BIMON projects in the sector.

## What BIM does on infrastructure

### Tender: price what you will build
On large infrastructure tenders the contractor has weeks to price kilometres of works and propose improvements. A model of the whole route lets the team verify quantities in the client's estimate, test alternative solutions and see their effect on time and cost before submitting.

### Design: coordinate structures, systems and ground
Bridges, viaducts and tunnels interact with geology, existing networks and the systems that run through them. A federated model of all disciplines shows clashes and gaps early, and produces drawings and quantities consistent with each other.

### Construction: 4D and 5D
Linking the model to the programme (4D) and to costs (5D) shows how the works progress, where crews and equipment overlap and how changes affect the budget. On linear works, the 4D model is also a tool to plan traffic diversions and possessions.

### Operation: a twin for inspection and maintenance
Once built, the model becomes the base for an asset register of structures and components. Inspection results, monitoring data and maintenance history can be attached to the same objects. This is where an infrastructure digital twin starts.

## Skurusund bridge, Sweden: digitising the existing and the new bridge
The new Skurusund bridge is part of road 222 Värmdöleden, east of Stockholm in the municipality of Nacka. It is 317 m long and 31 m wide, with a 99 m main span over the strait and two side spans on each side. The scope includes the Skuru and Björknäs interchanges, access ramps and pedestrian and cycle underpasses.
For 3TI Progetti, from 2019, BIMON digitised the existing and the new bridge, supported design activities and used the BIM model for project documentation and quantity management. On the Skurusund bridge the work produced:

- accurate 3D models enriched with BIM data, 2D drawings derived from the model and renderings;
- clash detection checks for coordination of services before construction, with a report and a coordinated multidisciplinary model;
- a 4D model linking geometry to the construction programme, to study constructability and feed back into programme revisions;
- 5D quantity take-off and cost estimation from the model.

## Naples-Bari railway: BIM from the tender stage
The Naples-Bari high-speed and high-capacity line is part of the Scandinavian-Mediterranean corridor of the TEN-T network. BIMON worked on two sections of 16 km each, Naples-Cancello and Cancello-Frasso Telesino, for a total of 32 km.
For Impresa Pizzarotti, from 2016, BIMON supported the bid from the initial procurement stages by creating the digital model of the entire line, including all bridges, viaducts, underpasses and tunnels. On the Naples-Bari railway we then studied design improvements and developed the full detailed design of the tunnels.
BIM was used for 4D and 5D simulations of construction phases, quantity extraction for cost estimates, technical drawings and photorealistic images to study critical aspects of the final design. Introducing BIM as early as the bid made it possible to optimise the proposed improvements and to verify actual savings in cost and construction time.

## Doha Red Line North: coordinating seven underground stations
The Red Line North of the Doha metro runs about 13 km north from Msheireb through seven new underground stations, with twin tunnels of about 11.6 km and an internal diameter of about 6.17 m. It is part of the mobility programme of Qatar National Vision 2030.
On Doha Red Line North, from 2016, BIMON supported Italferr in the management and coordination of all the stations on the line, and was responsible for the BIM detailed design of the plumbing systems for four stations. All discipline models were integrated in one aggregate model for interference management, and drawings were extracted from the models.
Underground stations concentrate structures, MEP and railway systems in a confined volume. Coordination in one model is the only practical way to keep them consistent across seven sites designed in parallel. We describe the management side of this kind of contract in ISO 19650 in practice.

## Naples Afragola station: coordinating structures and systems two weeks ahead
Naples Afragola station, designed by Zaha Hadid, covers about 38,000 m² and serves as an interchange for high-speed trains on the Turin-Salerno line. Its curved geometry makes coordination between structures and building systems particularly demanding.
For Astaldi, from 2015, BIMON was in charge of project optimisation in relation to construction. We built the BIM model of the whole MEP system, used it to identify and resolve interferences before construction and extracted the quantities of materials and components to be purchased. The model allowed coordination of physical overlaps between structures and systems about two weeks in advance of the works, and a constructive simulation of the whole work helped avoid unforeseen events on site.

## Examples from around the world
Some of the world's most advanced infrastructure projects, delivered by other organisations, show where this approach leads. The United Kingdom is one of the countries paying most attention to it.

### Crossrail (Elizabeth Line), London
Crossrail, one of Europe's largest transport infrastructures, adopted a comprehensive BIM approach to manage an £18 billion mega-project. The system integrated data from over 25 main contractors into a single source of truth for the whole project. The results:

- 20% reduction in construction time;
- 30% improvement in safety, with fewer accidents;
- more effective cost control.

The Crossrail Digital Twin is now used for operational management, keeping the infrastructure properly maintained throughout its lifecycle.

### High Speed 2 (HS2), United Kingdom
HS2, the UK's new high-speed railway line, is implementing one of the most advanced BIM ecosystems ever created for transport infrastructure. Digital models of the entire infrastructure are integrated with environmental, social and economic data in a comprehensive digital twin of the project. This approach has enabled:

- a 20% reduction in carbon footprint;
- better integration of the infrastructure into the territory;
- a significant improvement in public acceptance of the project.

The HS2 Digital Twin is also used to simulate the socio-economic impact of the infrastructure and to guide long-term strategic decisions.

## The regulatory frame in Italy
The legacy reference for BIM in Italian public works was Ministerial Decree 560/2017, with a gradual timeline. Since 1 January 2025 the rule is article 43 of Legislative Decree 36/2023: BIM is mandatory for new works and interventions on existing works with an estimated works cost above €2 million. Maintenance is excluded, unless the asset was delivered with BIM. Annex I.9 sets the requirements for contracting authorities, including the capitolato informativo and a common data environment.
For infrastructure owners this has a practical effect: the models delivered today on new lines and bridges will have to be kept alive in later interventions. Our guide to the BIM mandate explains thresholds, exclusions and transitional rules.
At international level, EN ISO 19650 is the reference for information management, and IFC 4.3 extends the open format to bridges, roads, railways and ports.

## How to get more from BIM on infrastructure

- Model at tender stage. It is the moment when design choices have the largest effect on cost.
- Agree the model breakdown along the route. Chainages and structure codes must be the same in models, programme and cost plan.
- Link 4D to possessions and diversions. On live networks, the programme is shaped by when you can work, not only by how.
- Survey existing structures. On upgrades and widenings, Scan to BIM of the existing asset avoids design on wrong data.
- Plan the handover for operation. Inspection and maintenance need structure codes and component data from day one.

## What BIMON does on infrastructure
We work with contractors and engineering firms from tender to construction: route models, design support, 4D and 5D, interference management and BIM management on multidisciplinary teams. On site we add site monitoring to keep the model aligned with progress. If you are pricing an infrastructure tender, a model of the route is the fastest way to check what you are pricing.