The following is simply from CreationTemplate.ini:

[TimeLineTrackTemplate]
[Float] = "Your timeline event text here" | "Your command"; NB: Float is a time in second (>= 0) 
;  after which this timeline event is going to be triggered; If the event is a valid command 
;  it'll get executed by the command module;
Loop = true|false;
Immediate = true|false; NB: If true, track will be executed immediately after being added to a timeline as opposed to during the next object update. Defaults to false;
KeepInCache = true|false; NB: If true, the timeline track will always stay in cache, 
;  even if no track of this type is currently in use. Can save time but costs memory. Defaults to false;