Oliver wasn't sure how he ended up in the train station. Someone at the help desk had given him the run down. He had somehow access the station through his dreams, and the only way out was to board a train. Initially, he had tried to find one going back to his own world.
That plan had been a failure since no one at the help desk knew where he was from, and asking them look up a world that was normal got him nowhere. Every world thought they were the normal ones.
The station had a signs that led to different worlds, and they seemed to be grouped by similarities. There were worlds of just men, just women, where people aged in reverse, so on and so forth. Within each option there was a junction leading to different routes of all the worlds with these features, though they were all slightly different he was assured.
Plan B was to find his original world, but he couldn't figure out how his world would be group, and all he could say was the options he found would not have his world there. This led to Oliver giving up and just picking something that sounded entertaining.
This was how he found himself at the junction of worlds where sex change was common. Oliver had seen movies where there was a body swap or someone lived a different life. Typically they were good at first, but then people saw the down side and missed their old lives. This way, he could take temporary benefits and change back before any of the long term changes set in. But which variation of this world should he go to?