Hi,
I think I'm about to ask a super-lame question, but what the hell...
I always thought that the little orange switch on a PF battery box was a reverser / polarity switch. So I've setup a small test train (battery box, receiver, motor) and tested it... and noticed, that it's not working as expected. On the other hand, the reverser on the remote control is working as expected (either forwards or backwards). I've actually tested two battery boxes and noticed the same behaviour.
What is the problem here?
Edit:
Ok mystery solved - it works when I connect the motor directly to the battery box. Looks like the receiver is ignoring the polarity of the battery box.