From Valve Developer Community
- Fired when the train starts moving in either direction.
- Fires continuously every frame when the train is moving to its next destination.
Note:This is incorrectly listed as "OnNext" AND its description is completely wrong in the default FGD!
- These Outputs each fire in response to the firing of the like-numbered
FireUser4Input; see User Inputs and Outputs.
OnKilled(Only in the Left 4 Dead series)
- This Output fires when the entity is killed and removed from the game.