There is no notification on the back of the photo.
An excursion on 16/04/1950 is known and probably the photograph was taken on that day as well. As the excursion took place on the route Leuven — Tervuren at that time and there are some people walking around who are clearly not passengers and also the terminus is clearly visible, it is reasonable to assume that the photo was taken in Tervuren on that day.

Author E. Bouman, photo from my personal collection.