Lüttich,	FN TB VI	Nr. 524
FN TB VB		Nr. 550
FN TB VI		Nr. 543

The exit was in another street and 50 years after closing the poles still appear to be present!
https://goo.gl/maps/PmCNEKcvLd38wNnL8

Photo: Herbert Heller (Belgium) negative and photo from my collection and written permission to use the collection in my possession.