not sure, what's requiring billions of euros, a full, factory new train (e.g. classic cars and a locomotive) built for relative high-speeds on existing rails (e

not sure, what's requiring billions of euros, a full, factory new train (e.g. classic cars and a locomotive) built for relative high-speeds on existing rails (e.g. maxing out at 160 to 200km/h) costs around 20-30Mio euros iirc (Austrian Railjets). If you go the used, traditional car route, you are more realistically looking at 10Mio euros max. So: the only problem is getting your route approved by all states network operators, which is a complex problem of congestion, neglect and slow, european style processes. Case in point (no joke): a hotel sued the Deutsche Bahn because some train tracks were not operating within the permitted legal framework. Now you say: that's a democratic, rule-of-law society. I say: the train has been there for 90 years, no living human has ever been at a disadvantage because the state pushed trough with the train without proper permissions... And of course, the rail needs to be high speed, because otherwise the environment, rail service companies and people could actually profit from the latter rediscovering how cheap and nice train travel could be... (for example: a single ICE (german high speed train, which generally goes 160-200km/h, because there is no dedicated high-speed-track) costs at least thrice the aforementioned Railjet and also more maintenance (higher safety margins for higher speeds) - now talk about the high cost of car/bus-rivaling rail again)