I went in 1980, a proper non stop boat train to Dover. Ended up in Athens, on the way down through former Yugoslavia in the middle of nowhere the train hit a tractor (apparently killing 3 people) it stopped about 2km down the line while they did whatever they had to do. About 6 people climbed out of the door and went sunbathing in the field. After about 3 hours the driver hooted his horn and drove on.
About 3 people managed to jump back on board but the others were left behind. I wonder if they are still there?
IIRC it would have cost about double the train ticket cost to fly back from Athens in those days. I was very tempted. You also had to pay half fare on the ferries, this was long before they built the bridges / tunnels but if you stayed on the train and got shunted onto the ferry you could go from (West) Germany to Denmark and then on to Sweden for nothing