Disclaimer I don't own anything but the story line enjoy.

RWBY pov: It started as a normal ( as normal as rwby gets) train ride and then the train was thrashed by water and a water Dragon Grimm. (The water Dragon has no wings and is black all over with a white mask made of bone if you didn't know) Team rwby want to fight it.
Authers pov: the teams wepons are called crescent rose for ruby rose
Myrtenaster for Weiss scheme
Gambol Shroud for Blake belladona
Eamber Celica for Yang Xiao long
Team rwby pov: