It could be a link between 2 stations ... maybe it's not bad to be simple!
I was also looking for a book published by Loco-Revue (LR-Presse) on railway signaling ... "the miniature network - the signaling in a few typical cases", thanks to the author Yann BAUDE, journalist at Loco-Revue, for me to have sent amicably ... and dedicaced in addition, a copy of his personal reserve (the edition is exhausted!) ... very [...]