After writing my last post, I did in fact play a lot of Minecraft. What I can tell you about spending most of your time underground is that you really lose track of time. There's no day, no night, only artificial light. Then you come above ground and you're surprised to find it's dark out, because it's always light where you've been. It's disorienting. I don't know if that's going to have any bearing on this next story, but it's certainly something to consider.
Now, in addition to digging all those tunnels, as I do, I've been laying rails. Minecarts. Transport. All that. So there's that railroad. Then I've just finished that story that starts on a train. And I'm nearly through Terry Pratchett's Raising Steam, which is about, you guessed it, trains. So I have trains on the brain. And I had a thought for the introduction of my main character, occult detective, who still doesn't have a name. And wouldn't you know it, it involves a train.
Imagine this: the story opens on some… something… happening, deep underground. A murder. A mysterious shadow in the dimly lit tunnels. I don't know. It's the teaser before the opening credits, if you will. We leave that unresolved a cut to our hero, on a train from somewhere. Maybe he's on his way back from his last job. He's about to be recruited by Miss DeWitt, on a mission of utmost importance.