There is currently no train service between Antequera and Granada, as the line is being upgraded to AVE/TGV standard.
The work is way behind schedule.
I was in Granada over Christmas and chatting to the tourist operators there, it is clear that there is no confirmed public date for the start of service.
Driving from Seville to Granada it was clear from the road after Antequera, that although much of the civils are now completed, a lot remains to be done on track laying and completion of catenary and power supply.
So for the moment, bus is the only option.
I have checked the Spanish press since returning and there is talk of the line being open in the 1st quarter 2016. However, there are problems with station facilities in Granada.
Methinks this is going to run for a while.
Update: 10 January 2016 Article in the Spanish press about the railway line to Granada:
However, Visit Granada!!!!
It was my 4th time and I love it!