RESA, bear in mind that the runoff is bounded by a railway trench. That's the steps and retaining walls you see.
Google Map (Simon from AVHerald used them too) shows the one end of the trench (for an airport rail link from Leuven to BRU) under construction. This is apparently the trench that the 742 would've gone into if it hadn't come to a stop. The trench was designed to ensure safe operation of the express services between Bruxelles and Leuven, and Bruxelles/Leuven and BRU without being affected by trailing vortices.
The rail link between Leuven and BRU is still inactive because of the kerosene that's still being pumped out of the tanks. Once that is complete, the rail link will be reinstituted.
In some of the media provided by Belgian newspapers, the trench is not even visible, because it is fairly deep (to protect the catenaries from wind/vortices) and narrow.
S.