Railmin is blue with cyan arms, blue ring-shaped hands, 2 round, orange shoulders, a blue appendix, a cyan face and red markings.
For his Bugmin ego, see: Bug-Railmin
As a Bugmin, when he opens his mouth, his teeth are always shown.
Railmin is a happy Promin who loves trains. When Railmin makes a noise, he says 'Shinko' or 'Batao-Batao'. However, when Railmin sees or comes into contact with any of Zuzumin's droplings or anything like them, he says 'Unko' or 'Reishi' instead.
- Yuto and Mirai (owners (Railmin is Mirai's Promin buddy))
- Zuzumin (rival/friend)
- Zuzumin's droplings (Railmin's dislike)
In the series
Railmin made his first camero appearance as a Bugmin in the beginning of episode 1.
Railmin's major role debut as a Bugmin was in episode 4 when he took both Wanda and Shuu on a railway rollercoaster. That was until Zuzumin stopped him with his droplings. Yuto then captures and debugs Bug-Railmin. Later, as his Promin-self, Railmin gave Yuto and his friends a train ride across the meadowy hills.
- Railmin is one of the first 6 Promins to be introduced in the teaser before the Kamiwaza Wanda franchise's debut.
- Railmin is the first Promin to be captured and debugged as a Bugmin by Yuto outside of Kirakira First Street. Bug-Railmin was captured and debugged by Yuto at a construction site.
- Railmin is one of the 4 Promins who became the Promin buddies of the 4 Kamiwaza Power-Shooters in the original Kamiwaza Wanda season. Railmin is Mirai's Promin buddy.
- Railmin was featured in the Kamiwaza Promin-Zu segment in episode 39.
- Railmin resembles steam trains and subway trains.
- Railmin has a dislike on Zuzumin's droplings and anything like them.
- Railmin's name comes from the word 'rail' which is a type of track that diesel trains, steam trains, subway trains and bullet trains all travel on.
- Railmin is also known for bringing other Promins in a Promin-Train with Railmin himself leading the way. In a Promin-Zu minisode on episode 4, 3 of the Promins, Turbomin, Tonkmin and Zuzumin, went separate ways without leaving Railmin's Promin-Train, causing it to end in a catastrophie.