John I love the lighting & presentation. Do you have details on how they "sanieren de Bodem"?
The whole city is heavy soil polluted. One reason is the textile-industry using chemicals, especially after WW I. Another reason is the train-maintenance site, which has been active in the middle of the city since 1863, all coal and diesel Locs were on the site in maintenance since that time. As there was no law regarding soil pollution, the old diesel and oil just went into the sand. They had to wait till it all was absorbed.
Another pollution source nearby was a gas-turbine factory which used all kind of fuel to heat the city. All added up, the problems are enormous, and keeping the stuff non-movable is one of the main policies.
In this case, as houses will be built there, the heavy polluted soil will be transported the to a chemical destruction plant. The lighter pollution will be placed on observation on special piles, till the test will reveal it can be used, or needs to be destructed too.
The new building site is behind the old wagon