Gaine can combine with Might Wing and Locomorizer to form Might Gaine, then combine with Might Kaiser to form Great Might Gaine.

Gaine's primary form is a Shinkansen 300 Series Nozomi Service bullet train. He is the first robot to be equipped with a Super-AI, which allows him to have human emotions along with excellent combat skills. He normally deploys alongside with Maito Senpuuji piloting the Might Wing. Gaine takes control of Might Gaine alongside Maito during the first half of the show but then switched to controlling Might Gaine all by himself after Maito becomes Might Kaiser's designated pilot.

Gaine first made his debut in episode 1 when a trio of thieves used their robots to rob a back, easily defeating them. Later that evening, he was deployed and confronted Dr.Wolfgang's Ether 5656 who was stealing electricity from a factory. The 5656 initially proved too strong for Gaine to handle, so Maito sent out the command to combine into Might Gaine, swiftly defeating the enemy afterward.

Gaine was the only member of the Brave Express Team's super-AI robots to survive the final battle.