No, the armed forces have their own fuel locomotives. I imagine any sizeable military does the same thing. Plus most (all?) cargo trains still use fuel. 100% electric is just passenger traffic.
replyhttps://www.outono.net/elentir/2021/10/23/the-spanish-army-r...
Maybe I'm looking at the wrong article, but there's this:
reply> For journeys outside the base, *the Army uses Renfe locomotives*.
which, in my understanding, means that in order to move military materiel (to the borders with France, let's say, or to the closest sea-ports most probably) and tens to hundreds of thousands of mobilised men the Spanish Army does indeed rely on Renfe locomotives, i.e not on their own.