Digimon The Movie 6
Runaway Digimon Express
A digimon train, Locomon is barelling along the tracks, racing through stations and almost colliding with other trains. Growmon is unable to stop the train. Takato manages to get on the rear car and tells growmon to let the others know what's going on. Ruki boards the train as well, and the two try to stop the train by putting out the coal in the boiler. It fails, but Beelzebumon arrives on his motorcycle and tries to stop the train. His guns are unable to stop the train and he's sent flying by Locomon's counterattack.
Jenrya, Hirokazu and Kenta plan on using a small utility tram to catch up with Locomon and it's revealed that Jenrya accidentally took Lopmon with him instead of Terriermon. Meanwhile, construction crews ordered by Yamaki are manually changing the track to force Locomon to a certain location. Yamaki finds out that Takato and Ruki are on board the train, and contacts them through Ruki's cellphone. However, while Takato's talking with Yamaki, Ruki suddenly attacks. It's eventually revealed that Ruki's being controlled by Parasimon, the same is happenning for locomon. Guilmon defeats the parasimon attached to Ruki, but then Locomon evolves to GrandLocomon. Grandlocomon cuts off the passanger cars, and Ruki tries to get to the lead car but is captured again by parasimon. Takato and Guilmon merge to Dukemon to save her.
After the parasimon is defeated, they learn that the real plan is for the parasimon to invade the real world by using the link forged by Locomon. Everyone goes mega, but there are too many, even when Justimon appears to help, they're overwelmed. Takato and Guilmon don't give up, and in a blaze of light, Dukemon Crimson Mode is revealed. Using his Quo Vadis attack, he defeats all the parasimon in a single blow. Locomon is freed, and his wish is the same as when he was controlled.
We flip to Ruki's birthday party, and you get to see a bunch of neat sequences followed by the end credits which could also be taken as sort of an epilogue to Digimon Tamers.