That's interesting.

When I go on the bahn.de website to input, I've stated that I'd like a train leaving "Berlin-Schönefeld Flughafen" and arriving at my final destination (which is Bielefeld, over near Hannover).

The train I'd like to get, the 18:50 one that I'm worried I won't make, says that it's a "Regional Express" or RE train as far as Berlin Hbf, and then an ICE on to Bielefeld.

The other train, the later one that leaves at 20:22, is a "Regionalbahn" or RB train to somewhere called Berlin-Spandau, then an ICE over to Hannover, and then I have a couple of regional connections to get to Bielefeld.

I confess to being completely clueless about this. At this point I'm hoping to take the taxi in to the Berlin Hbf as a way to make this easier. However, if I have a chance to get the RE train to the same location, should I do it? Is that the same as the "S-Bahn" you refer to in your post?

I think if I'm understanding you correctly, it is not. In other words, there is an S-Bahn train that I should avoid, and instead I should get the Regional Express directly to the Berlin Hbf. Have I got that right? And if so, how do I make sure I don't screw it up? Are the trains clearly labelled as "S-Bahn" or "Regional Express" or what have you?

Thanks again for your help.