This is a file from the Wikimedia Commons and may be used by other projects. Information from its description page there is shown below. Commons is a freely licensed media file repository.
Summary
DescriptionMuelleRioTinto1.jpg
English: The photo demonstrates the gravity system used to send the railway wagons to the end of the pier via the central track. A change of points enabled them to return to the beginning of the pier at a lower level to the left and right of the arrival track
to share – to copy, distribute and transmit the work
to remix – to adapt the work
Under the following conditions:
attribution – You must give appropriate credit, provide a link to the license, and indicate if changes were made. You may do so in any reasonable manner, but not in any way that suggests the licensor endorses you or your use.
share alike – If you remix, transform, or build upon the material, you must distribute your contributions under the same or compatible license as the original.