This story was written for general audiences, but it should interest rail travelers. The whole trip went Berlin > Frankfurt > Paris > Nimes > Barcelona > Valencia > Alicante > Madrid and then I covered the segment described in the linked article.
https://www.berlin1969.com/stories-geschichte/pyrenees-crossing/
There is other rail material in the Documents and Stories sections of the website:
https://www.berlin1969.com
https://www.berlin1969.com/stories-geschichte/pyrenees-crossing/
There is other rail material in the Documents and Stories sections of the website:
https://www.berlin1969.com