http://en.rocketnews24.com/2014/04/21/better-know-a-train-nerd-36-different-classifications-for-japans-densha-otaku/

36 different classifications for Japan’s “densha otaku”

1. Tori-tetsu: enjoys taking pictures of trains
2. Onkyou-tetsu: focuses on sounds made by trains and recording them
3. Nori-tetsu: enjoys riding trains
4. Ori-tetsu: likes to get off the train and explore around the station
5. Jushin-tetsu: intercepts train operators’ radio signals
6. Sharyou-tetsu: an expert on train cars, including design and engineering specs
7. Mokei-tetsu: a model train collector
8. Shuushuu-tetsu: a collector of train-related goods
9. Oshi-tetsu: a stamp collector
10. Suji-tetsu or jikokuhyou-tetsu: focuses on train timetables and maps
11. Eki-tetsu: station experts
12. Haisen-tetsu: experts in abandoned rail lines
13. Haisen-tetsu: a wiring expert
14. Senrou-tetsu: focuses on the rails themselves
15. Setsubi-tetsu: rail facilities fans
16. Unten-tetsu: conductor wannabes
17. Houan-tetsu: railway safety fans
18. Kaki-tetsu: train artists
19. Kakuu-tetsu: imaginary train builders
20. Ekiben-tetsu: lunch box afficianados
21. Chibi-tetsu: mini train nerds
22. Mama-tetsu: chibi-tetsu’s mom
23. Kaisha-tetsu: an expert on train companies
24. Kaigai-tetsu: overseas train nerd
25. Houki-tetsu: legal beagles
26. Soushiki-tetsu: literally “funeral otaku”, fans of final runs
27. Gunji-tetsu: military experts
28. Tetsugaku-tetsu: train philosophers
29. Reikishi-tetsu: history buffs
30. Tetsukei-tetsu: rail police fanboys
31. SL-tetsu: steam locomotive experts
32. Game-tetsu: train gamers
33. Ne-tetsu: train sleepers
34. Ekine-tetsu: station sleepers
35. Tori-tetsu: thieves
36. Kuzu-tetsu: jerks