After Christmas we spent four days in Madrid visiting Ana's friends and brother, who lives in Madrid and has just become a father for the first time.
We travelled to Madrid and back by the night train, in a sleeper carriage, which I've never tried before and don't plan to try ever again. We found ourselves trying to sleep in an ordinary railway compartment which had six rather narrow bunk beds (three on each side) in place of the usual seats. There wasn't enough headroom to sit up in bed, and the only bedding provided per bed was a sheet, a rather small blanket, and a tiny pillow. The bed was probably full of house mites as it gave me an allergic reaction.
We were travelling with Ana's sister's family, so we had the compartment to ourselves, but it was rather crowded with four adults and three children, and none of us slept well; the children seemed to survive the experience best.
We'd have been much more comfortable travelling by day, seated, in the normal way.