Sea Train

A Sea Train (海列車, Umi Ressha?) is an anachronistic locomotor in the One Piece world. To date, there are only two in existence, both built by Tom the Fishman, a reputed and legendary ship-builder from the city of Water 7.

22 years prior to the manga's current date, Tom was considering building a proper Sea Train when he was approached by representatives of the World Government, who sought the Fishman for the crime of building Gol D. Roger's pirate ship, the Oro Jackson. At the time, Water 7's remoteness and proximity to a large number of Sea King made the port city undesirable for trade, slowly eroding the city and all who lived there. By building his "steam paddle boat", Tom would effectively save Water 7 by opening it up for trade, as well as saving his own life. The Judge overseeing Tom's trial agreed to postpone Tom's crimes for 10 years; if he was successful at building the Sea Train Network, he would be pardoned for his original crime.

When Tom began construction of Water 7's Sea Train Network, he had already built a prototypical steam engine called the Rocket Man. After drawing up a new blue print. Tom's polished train, The Puffing Tom, was originally only connected to Enies Lobby, but Tom took an additional four years to build tracks to three other nearby islands: Saint Popla, Pucchi, and San Faldo.

By design, a Sea Train is roughly immune to changes in weather; the train's momentum and speed allow it to pulse foreword in any situation, even against an Aqua Laguna (a large storm that hits Water 7 every year). Whenever the train passes over the track, a device near the wheels makes an underwater dissonance that drives away Sea Kings. The tracks of a Sea Train lie just under the surface of the ocean, and sway with the tides to avoid resistance damage. The tracks require only occasional maintenance, as they are never really "used"; a Sea Train paddles on the ocean's surface, and only connects to the tracks as a guide to its destination.