I see that the times are from 1130z to 1900z. Do you still continue on your Track or if you would reach the actual Track after 1900z are you even assigned to a Track?

 

Trent has it pretty much covered -- all I would add is that if I recall correctly, the track validity is based on your ETA at 30W. If your 30W estimate is prior to 1900Z, you are on the track: if after, you are on a random route. However, your routing will have been sorted out before you enter Oceanic airspace: you just fly the route you have been cleared along.

Thanks to both of you.  B)