No, obviously Coruna was the main stop and Ferrol just an afterthought-or maybe what one calls ´political´ service-Ferrol (formerly called El Caudillo) was and is the main Spanish navy port-about like Plymouth for you?
I´ve done it a year of 4-5 ago, not from Madrid but halfway from Leon, having gotten there on the 1/day tiny FEVE narrow gauge tramtrain, and using it along the coats again back to Bilbao from Ferrol. That was a Talgo with the usual quite used and not too shiny anymore interiors-I think I was the only one in that carriage to get on all the way to Ferrol. Station at Leon was all closed off, but a guard on duty let me in after explaining my silly purpose and showing ticket etc.