Brussels to Köln should be Ok as these international services seem to have run during previous strikes, subject to the usual failures and cancellations of course, and even if your ICE (14:25 per chance?) doesn't turn up you'll be able to use other services as far as Aachen with the prospect of something to get you to Köln from there. If you are going beyond there, good luck!
One thing I've found useful is a handy link which, if you have a smartphone with you, can display departure and arrival boards for every German station. Very handy when things go wrong.
This is the link for Köln departures:
https://iris.noncd.db.de/wbt/js/index.html?typ=ab&style=qrab&bhf=kk&zugtyp=THA,ICE,IC,EC,RE,RB&SecLang=EN&Zeilen=50
You can edit it for arrivals, other train types, and other stations.
For example: change 'typ=ab' to 'typ=an' for arrivals; edit 'zugtyp=' to include or exclude train types which are pretty self explanatory; change 'bhf=' for different stations.
You can get the codes for other stations from this site
http://www.michaeldittrich.de/abkuerzungen/index.php though finding some can be difficult so best to do that before you go.
I've found these very useful when travelling and they are pretty light on data use if you are paying for roaming internet rather than using free wi-fi.