WB "Training"?
A “train” refers to a group of players moving from one champion or world boss to another in rapid succession. So, the WB train will kill whatever WB has spawned, then move on to the next as soon as they’ve killed it. The Queensdale train is similar — everyone moves from one champion in the zone to the next in a set order. They’re great ways for quick, easy leveling and/or loot.
OH GREAT there is a GW2 wiki page dedicated to different champ train areas.
Mud Bone – Sylvari Ranger
Train as in choo choo, all aboard!
We chug along from world boss to world boss. Next stop: Dwayna!