Thunderbirds 2086 is a Japanese anime series loosely inspired by the original Gerry Anderson Supermarionation series Thunderbirds. The series was dubbed in English by ITC Entertainment, the original company who produced Thunderbirds, but is not officially recognised as part of Thunderbirds canon, due to the non-involvement of either Gerry or Sylvia Anderson. Despite this the English dub of the series contains music and sound effects from Anderson's series Stingray, Thunderbirds, Captain Scarlet and the Mysterons, Joe 90, UFO and Space:1999. A total of 24 episodes were produced, but only 18 were shown on Fuji TV in 1982.

The plot of Marine Express can be described in two parts. The first part focuses on the people boarding the train and the problems they encounter on it. The second part takes place after the train has stopped at its half-way point, an island that used to be home to an ancient civilization millennia ago and has its fair share of secrets.

Junkichi is the son of a rich landlord, while Koyuki is the daughter of a poor lumber worker. The mismatched pair soon finds love, and against his father's wishes, Junkichi decides to run away with Koyuki to start a new life. But when Junkichi is called off to war, they make a pledge to sing the song of engagement everyday until they are able to reunite