Simon Robbins wrote :

I remember only a couple of weeks ago the Spanish government
anouncing that a warning had been received that ETA was going to
target the rail network and they were going to have to check all
20,000(?) miles of track. I've not heard mention of this warning
since, or was I dreaming it? (If so, I'll let you all know next
time I have a similar dream!)

The news you've heard were about France I think, not Spain.