Why won't lines appear in tracking analyst?

[StephenHilton]

I selected the tracks (as well as the smooth track) in the symbology section. The points are still there, but there is no line.

FYI: I'm using a shapefile with date and FID being analyzed.

Also another issue I have is I can't concatenate my date and time (when I try only time is selectable), do I need to switch to geodatabase?

thanks!

[DanPatterson_Retired]

Since it isn't possible to see your data set up, you will have to be referred back to Smoothing track lines—Help | ArcGIS for Desktop 

As for date and time, a geodatabase is the one to use if you need them both in one field since shapefiles don't allow for both, so the would have to be in separate fields