French trains

There are still routes and regions that are not easily accessible, and
apparently there's one big piece of the freight puzzle missing up near
Scandinavia that prevents total north-south transit harmony.

There are many problems in the European rail network, especially across borders where there are many lines missing or in bad shape. Train influencer Jon Worth did a project last year when he tried to cross all intra-EU borders (+Norway and Switzerland) and give the problems some attention.

But the big piece missing near Scandinavia was interesting. Are you refering to the Fehmarn Belt tunnel?

That's quite a complex statement about train travel in Europe which takes a lot of unbundling, which I'm not sure this is the place to do so.
I'm excited that a new passenger rail route has now opened up through the Baltic countries making it viable to reach Finland overland now, and that the route between the top of Finland and Sweden has now reopened so there is a 2nd overland route from Finland to London through Sweden and Denmark. Also that the Germany to Stockholm sleeper is back. There are many positive developments going on, and yes I have more positive views from train vlogs, I am glass half full, not glass half empty. It also depends on experience.

I am rather mystified by the "big piece of the freight puzzle missing"- firstly what does that have to do with passenger travel, secondly please expand, or is it just a blanket statement you have read somewhere, in some bit of news media.
There are now freight trains running from China to the UK, and a long term project to build a through line to India.

Tickets that need to be validated before boarding will always have a mention to that effect printed on the ticket. So there is really no need to be confused here. In fact the confusion is often the other way: People trying to validate tickets that don't need validating.

So just read what is on your ticket.

That the requirement to validate goes away is a double edged sword. Validating tickets before boarding used to be common because tickets were flexible. When I was a student I travelled regularly between the Netherlands and Belgium. Tickets were valid 2 months then, so if no conductor passed and clipped my ticket I could use it again a few weeks later. In France where this was also the case for domestic tickets they therefore required tickets to be stamped before boarding...

That now goes away., but so does flexibility.

"...Germany to Stockholm sleeper is back." Fantastic !

Likewise with reaching Finland by an overland route, great...another option other than the ferry from Germany dep. from Rostock to get to Helsinki.

I think I meant the belt, yes, I watch so many videos they tend to blur after a while.

and I recently watched this one

https://www.youtube.com/watch?v=30foJiPUrBA

Was in Rambouillet station a couple days ago, and, indeed, the slots on all the validation machines were taped over, with a sign saying there was no need to validate anymore. Took a closer look at my ticket, and saw it had that date printed on it. Guess they figure no one's going to take the same trip more than once on a given day.

I think I meant the belt, yes, I watch so many videos they tend to
blur after a while.

I'm not sure I would call it a big missing piece of the freight puzzle, but the tunnel will make things a lot better. Especially for passenger trains, it is expected to reduce the travel time between Copenhagen and Hamburg by two hours.

The Brenner tunnel will also have a huge impact, and there are many other projects currently under construction.