The server doesn't 'hang' when starting from a command line. You are seeing normal behaviour. This is seen on Linux/Unix as well. All output once it starts goes to the .log file, not the console.
When starting on Linux, I usually have to start as follows:
nohup RUN_<>_RS &
and let it run in background.
You can try to run the command and redirect output, but the window will still show and 'wait' for shutdown. e.g.
<server>_RS.bat > nohup.out 2>&1
Chris