Story: There is very little, to no overarching plot. If you had to pin one down, it would simply be 'Life Working for the Japan National Railway's Public Safety Force'. Each episode has its own plot, with a few two episode Min-arcs. There is not much in the way of progression for the story, but enough happens each episode to usually be at least a little engaging. The worst part about the stpry is that the jumps that it takes at points, sometimes skipping frankly important or interesting parts that you think would be a focus, can be jarring.
Art: Art is par for the course. The way the trains look certainly is quite nice on the eyes, having some unique designs and interesting color themes, my favorite certainly being the 'Mini-train Engine' that you see in the opening title, shown in more detail later in the series. However I did notice a few hiccups in the animation, with some objects and people appearing and disappearing in a few scenes. Not super noticeable or immersion breaking though
Sound: Not much to say on sound. They er...have lots of train sounds like chugging engines, horns and the whistle of steam. Can't vouch on the authenticity, but it was certainly interesting.
Character: Not much is done on building the characters up at the start. The personalities of the Characters are not very deep, each with at most one or two notes to them. The females in the story feel a tad too fan-servicy at times in both design and personalities. You can tell that the character designs for the main females were made for sex appeal. It can get a tad distracting when a tense moment is ruined by the camera briefly panning past a character like the busty Haruka at Chest level just to give you a nice clear look at her 'bounce'.
Enjoyment: It was by far not the best I've ever watched, but it was certainly enjoyable, and much better than I was initially thinking. Not warranting a re-watch in my opinion, but I'm glad I took the time to watch it through in its entirety and did not simply drop it after an episode or two.
Overall: Worth your while if you find that your current anime-watching well has run dry. Out of the 12, only maybe....1 or 2 episodes dragged for me. Just be sure you are not watching this one with your parents, small children, or someone who is sensitive about seeing a lot of skin bared. There are not tons of scenes that include the nudity, (with 'naughty bits' always just barely covered up by artistic convenience), but if like me, that stuff has little bother to you, give it a watch.
