Follow the instructions for the Pan effect (I reccommend going Nexus -> Northernmost Door, go north until you reach a group of red tiles, then go left until you reach the starry door, rather than going through five long worlds) until you reach the orange eye monster. Go one screen left and about a screen up to reach the place in the picture.
Go through the two patches of grass in the center (just above the mouse in the picture) to go into a sub area. Go through the door here into a room of ladders. The rightmost ladder leads to the railroad.
...Though, I seemed to have missed something. I was using noclip mode (see the third paragraph here for instructions on how to do it; the page is for Yume 2kki, but this process works on all RPG Maker 2000 games), and found the railroad using its exit (which is on the same map as the stabbing room), backtracking to find the correct route. However, there's a gap in the ladder (which has an invisible portion that is one tile too short to bridge the gap), so I can't truly make it over there. If someone can figure it out, tell us.
In the meantime, I suggest you cheat, like I did.