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 droplets or anything like them, he says 'Unko' or 'Reishi' instead.
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 droplets. 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 droplets 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.