I never owned Trainz 1.3, so I don't know if it came with a manual or not. The manual may be in the documents folder of your Trainz folder or you might look on the CD for it. I hope this is an original version of the game that you purchased. If it's a used copy, then it may have already been registered and you won't be able to take full advantage of the forums or the Download Station (DLS).
Welcome to Trainz.
Mike