Puffing Tom

The Puffing Tom is Tom's only fully functioning Sea Train. Puffing Tom was built during Tom's original ten year hiatus from government persecution, with significant improvements added over the Rocket Man.

Design
Puffing Tom's design was based on historical 19th century steam engines. It is a custom built 4-4-0 locomotive with the words Water 7 painted on its tender, that runs on top of the water with a track to guide it. The color scheme was green and red with orange and yellow lining. In addition to its tender, Puffing Tom carries several passenger cars. During its trip to Enies Lobby several of these were destroyed by the Straw Hat Pirates or the Franky Family. The Puffing Tom also has freight cars, only one of which was shown only briefly, a flatbed car, bringing lumber to Water 7. It was built by a fishman named Tom and his shipbuilding company, "Tom's Workers", Franky and Iceberg being among them. Tom built a ship, the Oro Jackson, for the Pirate King, Gol D. Roger, while Roger visited Water 7 and was found out by the government. The government wanted to sentence Tom to death, but when he presented his idea to build the Sea Train to pull the island Water 7 out of its depression, the government allotted the time needed, 10 years, for Tom and his workers to build it. There were a few failures from proto-types like Rocketman due to its unstable (and unstoppable) speed. The Sea Train now connects over four islands and allows for trade between them.

Events on the Sea train
After events in Water 7 Sanji discovered Robin was on board the Puffing Tom. Sanji stowed away after leaving a note/love letter to Nami about his plan. After the train was a short distance from Water 7, Sanji entered the Puffing Tom from his hiding place on the last car. He quickly subdued the soldiers in the rear car including Jerry of CP6. In the following car he freed Usopp and Franky. After luring T-Bone and his men into the two rear cars he cut them loose. Moving along with Franky and the disguised Usopp they encounter CP7's Wanze. Leaving Sanji to deal with Wanze, Usopp and Franky split up. While Usopp used his octoshoes to reach Robin, Franky became involved in a fight with Nero. All three people accomplish their task simultaneously and end up in CP9's car. A desperate escape ensues with the three of them and Robin in the three rear cars. However, Blueno's Devil Fruit powers and Robin's unwillingness to be saved thwarted the escape and led to the recapturing of Robin and Franky. The Puffing Tom and its remaining cars continued to Enies Lobby.

Escape from Enies Lobby
As the Buster call razed the government stronghold, the Franky Family, Galley-La foremen, and the giants commandeered the Puffing Tom and escaped back to Water 7.

Trivia

 * The Puffing Tom's name is based on the oldest locomotive in existence, Puffing Billy. As stated by Oda in SBS volume 39.