From Anime News Network:
Kikuchi Naoe is a struggling manga artist in need of work. She lucks out when she runs into a travel writer and is asked to tag along. He turns out to be Yokomi Hirohiko, the Japan's biggest train enthusiast. In 1995, he visited all 4636 JR train stations. Now he is going to visit the remaining 5207 private stations. Kikuchi, despite her inital horror at her task, is stuck, as her boss is a huge train geek too. Thus, having few other options, she resigns herself to trying it out and henceforth accompanies Yokomi on his journey around Japan. [This series is non-fictional ]