Resumen
Railways managers and owners have to face several challenges to ensure commuters? safety and durable operation of their costly infrastructures and buildings which contribute tremendously to economic development. Whatever brand new or ancient railways infrastructures are concerned and according to heavy operation constraints and to consequences of any unwanted service disruption, the accurate, periodical and updatable evaluation of the condition of environments, structures and equipment is one of these challenges. The vast potential of contact-free innovative methods based on laser scanning and photogrammetric coverage developed accordingly is illustrated here by three recent real-cases: an ancient but congested railway concourse in Paris, retaining walls and tunnels of a new intercity line where increase in train frequency is already foreseen. Operating principles, technical features and benefits of these innovative methods developed to solve operators? complex technical issues are described in this paper. Structural condition of ancient truss-girder railway concourse through contact-free deformation measurements, complete tri-dimensional geometry as well as structural condition of long soil nail retaining walls and underground tunnels using a compact laser-scanner and photogrammetric coverage semi-automatic device were successfully surveyed and assessed, providing operators reliable and extensive data.