This is a story that's been told a million times. Seriously. The story is not anything special. That "mellow" in the title is not there for nothing, however (even if I wonder if it's a tiny mistranslation that should have been "melo", lol). This special gives a very laid-back, soothing sort of vibe. The scenery is pretty, the camera work is very nice, and all that works in its favor. However, there are several weird jumps in the story that mar the overall effect, to the point that I was a little confused in a couple of places. They're together, then next scene they aren't; she's angry, then she's in love, etc. The big one was towards the end, when I really had no idea where they were or how they got there (physically, or story-wise). Ultimately, I think it mostly made sense, but in those moments, it was jarring and took me out of the story.
It was nice to see the heroine grow up a little over the course of the hour. The hero, however, could use a lesson in communication. I was left wondering at the end if he had in fact told her his secret or not. Hmm. My vote is that he did, but it doesn't really matter.
I did like the role the train played. Trains and train stations were the setting and eventually a metaphor for the whole shebang.
I'm not much of a fan of love stories in general, so I probably shouldn't have even bothered with this, haha. Recommended if you're looking to spend a lazy hour looking at the pretty and not trying too hard to make it all make sense. And if you're not easily frustrated by stories that go nowhere fast. Or nowhere at all, haha. (Kind of like the train line in the show...was that an intentional parallel? Probably not, lol.)