BIM in Overhead Line Planning: Where Are We – and Where Are We Headed?

Building Information Modeling – BIM for short – has been a trending topic in the construction industry for years. High-rise buildings, tunnels, bridges: everywhere there is talk of digital twins, coordinated models and seamless data flows. But what is the situation in a narrow specialist field – overhead line planning for trolleybuses and trams?

The honest answer: BIM has arrived, but the industry is heterogeneous. Planning firms that want to make a difference today must not only know the technology – they must also understand where the method genuinely adds value and where it would simply mean extra effort.

What BIM Means in Overhead Line Planning

BIM is not software – it is a working method. Instead of isolated CAD drawings, a coordinated digital model is created that combines geometric, technical and organisational information.

In the context of overhead line planning, this means in practice:

• 3D route design of overhead line systems in the terrain model, coordinated with the track body, road space and buildings
• Clash detection between overhead line components and other trades (civil engineering, utilities, vehicle gauge)
• Attributed components – every mast, every line section carries information on material, manufacturer, installation year, maintenance interval
• Consistent documentation across all planning phases – from the preliminary study to the as-built drawing

The difference from the classic 2D drawing: the model remains usable throughout the entire lifecycle – even after commissioning, for operation and maintenance.

Where BIM Stands in Practice Today

Anyone working on Swiss urban transport projects encounters a wide spectrum: some transport operators and main contractors already require coordinated BIM models as a contractual requirement. Others still work entirely with 2D CAD drawings and paper-based handover dossiers.

Overhead line engineering is a niche segment. The major BIM software manufacturers have developed their solutions primarily for building construction and general civil engineering. Specific libraries for overhead line components – cantilevers, catenary systems, feeder points – often have to be built from scratch. This requires an initial investment that only pays off over multiple projects.

Clients vary widely. A large transport operator with its own BIM coordinator has different requirements from a small civil engineering office that primarily expects PDF drawings.

Standards are lagging behind. VÖV guidelines and relevant standards for overhead line systems have so far only addressed BIM marginally. Many planning firms therefore work with project-specific agreed standards.

Where BIM Really Adds Value

Not every investment in digitalisation pays off equally. In overhead line planning, the real benefit shows most clearly in three areas:

Coordination with Other Trades

Tram and trolleybus projects are typically collaborative undertakings: track construction, road construction, utilities installation and overhead line assembly run in parallel. A coordinated 3D model makes conflicts visible before they become expensive on site.

As-Built Documentation and Lifecycle Management

Many existing overhead line systems are poorly documented – drawings are outdated, component attributes are missing. Structured digital capture creates the basis for well-founded rehabilitation decisions and efficient asset management for the operator.

Variant Comparisons and Feasibility Studies

In the early planning stage, a parametric model enables rapid variant studies: how does the mast positioning change if the route shifts by 50 cm? What are the consequences of a different alignment height? What was previously manual calculation can now be answered model-based in a fraction of the time.

Our Approach at BayTech GmbH

We regard BIM not as an end in itself, but as a tool. Our approach:

• Scaled to the project: Not every project needs a fully coordinated BIM model. We apply digital methods where they deliver measurable benefit – and do not hesitate to rely on proven 2D methods for smaller projects.
• Open interfaces: We work with IFC-based exchange formats to ensure compatibility with our clients' systems.
• Knowledge transfer: We build project-specific component libraries that the client can continue to use for their own operations after project completion.

Conclusion: Digitalisation as a Quality Indicator

The question is no longer whether, but how BIM is used in overhead line planning. Firms that invest in digital methods today will have a noticeable competitive advantage in three to five years – compared with providers who have missed the shift.

For clients, this means: for your next project, it is worth asking specifically about a planning firm's digital competence. Not as a checkbox, but as an indicator of quality, efficiency and future readiness.