Good afternoon sheilasworld,
My name is Krista and I am with Nova Scotia Tourism.
Traveling from Pictou to Truro is about an hours drive; therefore you may want to look into reserving with a local shuttle service that travels daily from Cape Breton to Halifax. Where both locations are on route if you wanted to stop in Truro and then take the train it would certainly be possible, your other option would be to continue on the shuttle into Halifax.
A few companies I would suggest to you are:
Advantage Shuttle - 902-227-7276
B&N Shuttle Service - 1-800-330-4223 or 902-562-9893
Brennan's Shuttle - 1-877-847-7267 or 902-737-1265
Cape Shuttle - 1-800-349-1698 or 902-539-8585
East Coast Shuttle - 1-800-873-5551 or 902-794-1512
I hope this information helps!
Cheers,
Krista