From the S-Bahn platform the observer has great views on almost all incoming trains from the Hohenzollern Bridge over the Rhein river. The great roof construction of the station is the reason for the best train noice and station voices you can imagine. The cologne central station is also the crossing point for many important railway routes accross Europe. Thus the railway enthusiast can expect a great diversity in trains passing through the station. You can also walk to the Hohenzollern Bridge to enjoy train motion in slow motion, howeverb the metal contruction may be disturbing when filming.