What could this mysterious structure be? A dike? Unlikely, give its relationship with the river Dijle, not 25 metres away and intersecting it diagonally. A disused road? Well, there are plenty of used roads around, and this one doesn't appear to go anywhere.
But if you trace the ridge back into the village, you will eventually find that opposite the railway station (itself somewhat dilapidated) is this building (ignore the strange man in red shorts checking his Blackberry):
This, believe it or not, is the former station in Sint-Joris-Weert of the steam tram line which ran between Tervuren and Tienen from 1905 to 1957. If you look over the door you can still see where the name "Sint-Joris-Weert" would have been written, over half a century ago.
An easy enough Saturday outing. All photos taken by young F.