The ash cloud seems to have dispersed enough for life in Europe to resume as normal. Meanwhile, local politicians are talking about Rail Baltica again.
Now, I'm a big fan of high-speed rail. In Western Europe, it is the most comfortable way of covering long distances. Certainly a Eurostar, Thalys or ICE train between major cities will take as much time as a flight - considering that airports are far out of town and you have to spend a lot of time on security procedures - and it's just far more pleasant. You even get a nice view. Trains are actually often more expensive on these routes, but again, no travel to the airport, and overall I think it's worth the premium. In any case, if there is more demand for rail travel, prices are likely to go down.
So I would absolutely love it if Estonia had a railhead capable of supporting a bullet train all the way into Berlin. Even between Tallinn and Tartu, the express train is a better experience in most ways: a first-class ticket costs the same as the bus, but you get free tea and coffee, better access to power sockets, and a smoother ride. The express train only has two downsides: one, there aren't enough of them in a day - which makes it hard for them to compete with buses that run every half hour; and two, the Tartu train station is very inconveniently placed. The bus station in Tallinn isn't completely central either, but it's still less of a hassle than the train terminus on this end.
Estonia is actually making a useful effort at improving its rail infrastructure, the government is saying that trains will run at 120km/h all the way down to the Latvian border next year. But are we really desperate for a high-speed link down through Riga, Vilnius and Warsaw?
There's always Stockholm.
Apparently Stockholm to Copenhagen is a five-hour journey, with pretty frequent departures. From there it's a night train to Cologne, which is a major hub for ICE and Thalys (the German and French fast train networks respectively). Take the Tallink night ferry to Stockholm, and you can be in London within a day of disembarking.
Yes, it's a lot slower than air travel. But it's a lot faster than driving down through Poland. And the opportunity is already there.
In fact, now I kinda want to try it!