I have been trying to collect them all, but... on the station list there are 25? listed, Plus 4 depts I have got all (been over root 4 times) but am credited with 24/25. I even looked in sidings.
This guide is for TSW 2 on Steam, but regardless of the platform and TSW version, it should still help you find your missing collectible.
"Mind the Gap" I visited each of the 25 Stations now (4 times) and the poster is there where it should be,
