I did not find any thread on Luxembourg covers, so here we go
I picked up this item the other day:

TPO / Ambulant cancel 'Schimpach-Kautenbach F.C.", 17th June 1916. I believe the 'S' indicates soir (evening).
However - I am curious about these two cancels / cachets:
- The small circle postmark '150'
- "Auslandstelle Trier Freigegeben".
The last one make me think it has something to do with crossing borders / censorship, keeping in mind this was mailed during WW1. Can anyone verify - or even better correct and clarify?
If so, the letter must have passed through border control at Trier, German town, close to the border with Luxembourg, and then passed on to the destination in Brussels. However Schimpach and Kautenbach is in the North of Luxembourg, so I don't make sense of the route this travelled


Possible route (blue dots) ?? Borders in red
Unfortunately the letter is incomplete, so I am unable to see where it was mailed from. Possibly it could have originated from Germany (there is also another Kautenbach in Germany which would place Trier almost midway between Kautenbach and Schimpach), through Lier into Luxembourg. Them travelling TPO on Kautenbach to Wiltz, connecting with Belgian railway system...
Any viewpoint would be highly appreciated, I have never before attempted to track the route of any TPO mail before. And I did not find any sensible on google about the Schimpach-Kautenbach railway route. Could need some advise

Sidefact - Shimpach Railway station was shut down in 1967
https://translate.google.no/transla...pach-Wampach