vocal in x series

The delay's "tail" will exist only during the clip if applied to a clip. If there is no clip, then there is no longer a clip for the effect to process.
 
There are several possible solutions. I suggest cloning the vocal track but without any events. Split the words you want from the first track and drag them into the second track. Apply trimming to these clips of individual words. Now extend the end of the clip for as long as you want the delay to last if you want to use clip effects. If you're applying the same type of delay to all words, then just insert the delay in the FX bin for the second track.

I have never used a bus or automation im not a power user but Mr Anderton is closer to how I would work. Although I am not ruling using busses as I would like to start using them on midi instruments.

If I want a single instance or maybe a couple of instances of an effect I use the clip fx bin. As Craig pointed out you may need to extend the clip if you don't want the tail cut off.
 
Any more than a couple of instances I use a buss and control that via send level automation.

1. Create the buss in the buss view (Right Click "Insert New Stereo Buss")
2. Insert necessary effect on buss and set up as required
3. Rename buss to something meaningful
4. Select required tracks. In track header right click, hold ctrl key down and select ""Insert send" - Choose send from list.
5. Control send level via automation envelope.

HTH

I will have to try some of the points made as I want to try vocals and midi instruments on a track with the sends that you have suggested. Thanks