Activities relating to the design of rail infrastructures involve everything that is rail-relating: rail tracks, civil engineering structures, stations, street furniture, the catenary, electrical power supply and control/command systems.

When creating new lines or renovating existing structures, engineers carry out a series of studies, developing the necessary solutions and then monitoring their implementation on the ground. This ranges from geotechnical studies to the installation and maintenance of electrification or telecommunications equipment.

In addition, throughout work on a site, experts are involved in project management, project management support or SPC (Scheduling, Planning, Coordination).