Two hours by plane usually ends up as four and a half in total when you factor in time at the airport, plus you can turn up at your destination first thing in the morning feeling refreshed rather than tired from travelling. Then once you factor in the stress, noise, environmental impact and delays that come with flying, the night train becomes a really attractive option.
On a plane, you may have to get up extra early, or still lose half a day. Especially in Central/Eastern Europe, the prices aren't that high really. And, as GP already wrote, you save on one night in a hotel, which may offset the entire difference.
Also, there is the environment. If that were factored in properly in the prices (and that's being worked on), the train would be a lot cheaper.
I don't think you can really consider the environment here as there are too many variables to consider in a reliable model. E.g. its not clear that replacing that entire planes worth of peoples trips with another routing would even net a gain, if people might have to do more circuitous routing that take more time and distance, or take different modes of transit that aren't a fully electrified rail that goes end to end, e.g. a lightly filled bus that has a much lower per passenger mpg than an airplane.
I understand that some comparisons with realistic assumptions have been made. Notably, high-speed trains cause significantly more emissions than classical trains, but are still better than planes.
Add an hour commute to the airport, another hour at check-in and security and 10x the emissions: it's actually a fun experience going by night train, especially when traveling with kids.
Per passenger mpg between a train and a plane isn't all that far off. Planes tend to travel pretty full so per passenger mpg is pretty high, like 100mpg. You get better per passenger mpg with a train but the train needs to get decent ridership. Depending on where you are going, maybe the train and bus service doesn't get too much ridership and your flight in might actually work out to be the greenest way.
A key advantage of trains is they can be fully electric and don’t need to carry their entire fuel load on board.
An electrified train running on nuclear or wind supplied power basically can’t be beat for low-environmental-impact long distance travel. And even for non-electric trains, diesel trains with a mere 23 people per car have a BTU per passenger mile of 2,000, compared to a typical 30mpg car’s 4,000 BTU per mile.
And even if it’s not yet electric, buying the right of way and building the rail lines is better preparation for that future all-electric world. Plus the more trains exist, the more full they’ll typically be, and the better we’ll get at making them more efficient.
Radiative forcing-wise, flying emits 200g equivalent of co2 per pax-km, rail about 20g. And that’s largely due to infrastructure, so the marginal „cost“ of more trains is low.
The marginal cost of more trains being low depends on there being infrastructure at all, and some countries and areas are much better built out for this than others. For example, whats the marginal cost of another high speed train from Tokyo to Osaka? Probably low, the high speed tracks are already there and there is probably ample platform capacity at either end. Move east to Califnornia and whats the cost of adding another high speed train from SF to LA where there wasn't one previously? We are looking at north of 100 billion dollars here for this link and years of work. Quite a mountain of money, time, and effort, compared to e.g. scheduling another plane to land even at a tiny airport in an impoverished country.
It depends on what you want to accomplish. For a business trip it’s not amazing, but when you go with kids on vacation the night train is quite appealing in comparison with a flight.
Honestly given the difference in environmental impact idk why it matters. Flying is simply nit sustainable and should generally simply not be an option.
Just to be clear it currently is commonly the only option, but that must change