So I had booked a ticket via Trainline from Bruxelles-Midi to Cologne. As it happens, I'm on the train now, but not without a lot of very last minute hassle and angst.
I had come in from Bruges and had a 2.5 hr wait until departure so decided to spend most of it in a beer garden across from Midi station. Knowing that track assignments aren't usually known until at least 30 mins before departure I didn't think I had to worry about anything. But then around 45 mins before departure, I walk back in to see a "supprime" notice for my train, and that it is now, in fact, departing from Bruxelles-Nord.
So trying to keep as calm as I could, I immediately went out and grabbed a taxi to Bruxelles-Nord. As the driver was quite helpful and made it there in good time, I gave him an extra good tip. But I initially couldn't see anything on the departure boards for Cologne, and was starting to get quite worried. Luckily, I happened to be sitting beside some British women who were also supposed to be on that train, and everything worked out in the end.
I've never had anything but good things to say about Trainline, but I guess that is one major drawback. I didn't get any notifications that my train was leaving from a different station, whereas I might have if I had booked with DB or the Belgian train company. Do last minute switches like this happen often, especially for international routes?