The next to real time data can be found at:
http://reiseauskunft.bahn.de/bin/bhftafel.exe
The arrival times shown here are similar to the times shown directly at the train station. But you have only a very limited time frame, where the real time information is displayed (around 20 minutes before the train arrives).
However I agree with all the posters above. It can easily happen that a minor problem can lead to a delay of 2 hours. And also the S-Bahn can easily be delayed by 20-30 minutes.