With the proper planning it does not take long to organise a drone crew to carry out an inspection. Drones can be airborne after a flight assessment and imaging a roof for faults, damage and general wear and tear.
Document extensive amounts of track with a fixed wing or rotorcraft drone. Take into account the surrounding conditions which might be impacting the overall stability of the tracks.
Some areas are just difficult to access. But a drone and a skilled crew can access almost all areas within regulation.