System engineering & architecture, Complex and multidisciplinary projects, ERTMS, Interoperability, Operation, Maintenance


Constructing a new transmission line or modernising existing infrastructure is an increasingly complex operation with a growing number of interfaces: technical interfaces between the various subsystems (such as equipment-equipment or equipment-infrastructure), interfaces with existing infrastructure and any related projects, but also interfaces with operation and maintenance. For such projects to succeed, a systematic approach with a global understanding of the issues is therefore essential; and this holistic approach must take into account many aspects such as safety, operation, profitability, functionality, technique, service interfaces and limits, performance, migration, industrial issues, planning, testing and commissioning, contractual requirements, etc.

GESTE's team of engineers, technicians and experts have solid multidisciplinary experience in managing complex projects and implementing true system engineering. For example, we are involved in constructing new railway or metro lines as the systems engineer in charge of interfaces. We also have solid experience as a system architect and interface manager for the deployment of global signalling systems such as CBTC and ETCS, systems with numerous interfaces between - among other things - equipment, infrastructure, operations and safety.

Domains of activitiy

  • Railway, tram and metro lines and networks, whether existing or under construction
  • Rail and bus stations
  • Depots and garages
  • Tunnels
  • Junctions and rail/road sections
  • Self-driving and innovative vehicles


A transport system is made up of many subsystems which interact together with the common and coherent objective of ensuring passenger transportation. Together, they meet precise overall requirements for functionality, performance and safety.

System engineering is an interdisciplinary and global approach. It studies the system as a whole, as well as the development of the various subsystems. Using a structured method, it manages the complexity of the whole and reduces risks when integrating several subsystems. It also helps plan and monitor developments throughout the life cycle by means of milestones, reviews, expert opinions and integration points.

System engineering is an interdisciplinary and global approach. During the study phase, it studies the system as a whole, and derives and allocates the overall requirements to the various subsystems. Then in the implementation phase, it integrates the various subsystems with precise sequencing, making it possible to reduce risks and achieve overall qualification with respect to user needs. It also helps plan and monitor developments throughout the life cycle by means of milestones, reviews, expert opinions and integration points.

The overall approach to system engineering is summarised in the V-diagram of the life cycle, where activities at the 'system' and 'subsystem' level are distinguished.



  • System engineering
  • System architecture
  • Multidisciplinary projects
  • Interface management
  • ERTMS & Interoperability
  • Operation and maintenance concepts


For optimal management of our systems engineering projects, we apply ad hoc processes, which have been developed and optimised on rail projects (like AlpTransit Gotthard) or automatic metro projects (like the metros in Copenhagen, Greater Paris or Brussels).



  • Definition of system requirements
  • Functional analysis and general functional and technical architecture
  • Definition of functions and system architecture
  • Definition of functional, technical and spatial interfaces
  • Specific system studies (performance, reliability, availability, safety)



  • Definition of validation requirements
  • Definition of specifications and validation procedures



  • Integrated test management
  • Validation and commissioning



  • Migration studies
  • Planning and testing



  • Quality management
  • Requirements management
  • Configuration management
  • Management of functions and system architecture
  • Document management



  • Management of functional, technical and spatial interfaces
  • Management of service interfaces



  • RAMS (Reliability, Availability, Maintainability)
  • S (Safety)


We apply an integrated approach using project management software and interface processing such as

  • BIM
  • Configuration management (Lascom AEC, ClearCase/Rational, etc.)
  • Requirements management (Reqtify, Relatics, Doors, etc.)
  • Document management (SharePoint, ProjectWise, etc.)
  • Requirements management

We also develop our own software and tools that are perfectly adapted to our processes, in order to respond as quickly as possible to the needs of our projects and our customers.