When my son was around four or five years old he made me buy the "Safari" set. That engine only went forward also. I remember he played with it a couple of times and would pick the engine up and turn it around to get it to go the other way.
If I remember right it had a nice cardboard scene that came with it, along with a mat and some animals in a gondola. It was a real eye catching set but that one way engine was a real loser.
I guess that was around the late ninties when that came out. So what "ed" says above sounds about right for the time frame.
Mike played with it only a couple of times then it went into the box and under the platform. I guess you would say it's in like new condition so I will keep it the family for another hundred years and we will clean up on this fine collectable.