As a contrast to the previous grammatical mouthful, I offer this novel: 妹!妹!!妹!!!, read as “Mai! Mai!! Mai!!!”, neatly stripping the genre to its essential truth: “Little Sister! Little Sister!! Little Sister!!!”.
Having nothing to do with trains is 妹ChuChu, read “Mai Chu-Chu”, for “Little Sister Kiss-Kiss”.
Opening a different vein, we have ツンマゾ!. Read as “Tsun-Mazo!”, for “‘Aloof’ Masochist!”; just in case you miss the point, the theme is clearly explained in the subtitle. And the cover art.
Longer, but spelled out in phonetic Engrish for the benefit of the younger reader (or, well, not), is ミルクプリンセス ラブラブにゅ~トピア, or “Milk Princess Love-love Nyuu-topia” (nyuu being the reading for the kanji 乳, “breasts/milk”).