Expanded high-speed rail network part of vision for Europe, says EU’s transport chief

That's good, thanks for that info. It does say it's a "good will" gesture from the various train companies, but it seems to be a firm offer - would be good to have it enshrined in law nevertheless.

From what I read, you need to get a Delay/Cancellation Confirmation somehow. You then would need to book a seat on one of the following trains - on some routes, most trains are full by the time of travel, and in the event of a delay like this, you're probably not the only one needing to reschedule. You may well need to get a hotel overnight and travel the next day. All possible, but potentially stressful.

I will still avoid getting long distance trains with connections - but saying that, none of the several international train journeys I've made so far have been delayed more than 15 minutes.

Missing a connecting flight is no less stressful - and I also always avoid those as much as possible, although because long-distance flights are shorter, the knock-on effects of missing a connection tend to be less (more likely to be able to find a seat on a replacement flight on the same day for instance).