Himeko: By the time you read this letter, I'll probably be gone. The coffee machine is in its usual spot. I've left a few varieties of beans, though I doubt they'll be enough to satisfy your tastes. Once the Express sets off, you're bound to run into all sorts of problems, but knowing you, I'm sure you'll handle them just fine.
Regarding the Express's engine, I've combed through every data bank and train log I could find, yet not a single record documents how to start it. It's as though everyone has conveniently chosen to ignore it, or perhaps... simply taken it for granted. This train is lined with cutting-edge devices that showcase the pinnacle of interstellar travel technology, and yet its most critical component remains primitive and utterly incomprehensible.
I initially assumed it was a fuel issue, but the interface showed reserves were more than sufficient, enough to sustain well over a decade of voyaging. That was when an idea began to take root in my mind: The Express practices its Path by Trailblazing into territories never before stridden, drawing energy from the Path of the Trailblaze. Naturally, this kind of energy derived from the Path of Trailblaze wouldn't behave like ordinary fuel that can be lit with a flint or a fuse. The breakthrough came that evening. After you learned the ignition success rate had dropped, you lost heart completely. And the very next day, the success rate plummeted to its lowest point since we first discovered the Express.
What is taken for granted? What does it mean to walk the Trailblaze? What is the one thing you need as you take the very first step? The answer is written right there in the riddle. It's simply the desire to take that step without hesitation, without needing further reflection, to simply Trailblaze. The Express never turns away anyone yearning for the Trailblaze. Even if it lands in a world where something as simple as starting a fire becomes hard, humanity will eventually venture forth, and so will the Express. Your trepidation and lack of self-confidence have actually cooled down the train's already-ignited engine.
That is to say, the key to starting the Express has been in your hands from the start. We were so fixated on the odds of success, we forgot: the Trailblaze, by its very nature, means doing things no one has done before, and reaching places no one has ever reached before. This means, inevitably, a day will come, bearing setbacks and failure. But as long as you still carry that urge to go further than anyone before you, the Express will answer your wish, ignite its engine, and set sail once again.
From now on, you can no longer rely on my help. You'll have to walk this road on your own, and grow into a person that today's version of you yearns to be. And then, you'll meet so many companions worth relying on, and encounter people and things beyond anything you can imagine right now.
So don't be afraid, and don't hesitate. Just soar higher and higher. I believe in you.