Which European country has the most frequent train travellers?

This is the wrong statistic! It doesnt matter how often you take the train, but how far you go. There is something called a passenger kilometer. Someone traveling one kilometer by train makes one passenger kilometer, 6 people on a train going 10 kilometers makes 60 passenger kilometers. The same can be done for other modes of transportation. The modal split (the right statistic) then shows how much each mode of transportation is actually used. Here you can find the statistic for each country of the EU: https://www.eea.europa.eu/data-and-maps/daviz/passenger-transport-modal-split-2#tab-chart_1

A few examples why modal split is better than frequencies:

Environmentally CO2 is emitted per kilometer. Someone may bike a short distance everyday to work, but visits his parents who live far away every weekend by car.
On the way to work someone could take the car and the train on the same commute.

It isn't necessarily wrong, it's just two different metrics meant to measure two different concepts.
- Thanks for your comment. Not wrong in the sense that the data is wrong or faked, but that the metric is not useful. Especially when better metrics are readily available for that region. Can you name me one prediction or result which you can infer from the frequency of train travel other than „fun facts“? (I am actually really curious :) ). With the modal split you can for example calculate CO2 emissions or estimate needed capacity increases if you want to replace one mode with another and much more.
Switzerland is also on top for person-kilometres.
Model split also has it's downsides. For example:

Not every trip is the same in every country. Denmark commutes 22km on average, the Netherlands does 3km

Not every country travels as far. Someone who does 10km by train out of 100km has a much greater share than 20km out of 10.000.
Germany, would be better in Case you would measure the time that it takes to travel.

Danks ju för traffeling Wiss Deutsche Bahn ...
- Even that has problems. German railways might not be on time, but most of the main lines are upgraded to 200km/h and some new lines are even faster. So compared to for example Switzerland that means higher speed, but it is much more likely to be delayed.
Sweet link! These stats are really cool. Low car and high bus usage seem to be very linked to poorer (relatively) countries. High train usage in general seems to be much wealthier countries, yet those countries also have way more car usage. Also this is very incomplete without looking at bicycle usage, and walking of course. This makes the percentages even more misleading because it's a percentage among sampled transportation modes
- Thanks, and good observations. Many countries (Germany and the Netherlands for example) have statistics for every mode of transportation, which as you said is way more informative. I just quickly grabbed the first statistic I could find for the EU to be honest :D
  
  Here is the data for Germany: https://www.umweltbundesamt.de/daten/verkehr/fahrleistungen-verkehrsaufwand-modal-split#undefined
  
  For the Netherlands they have the data split by county which is very interesting. In the bike capital Utrecht still 50% of all passenger kilometers belong to car travel. I cant find the government website right now.
Interesting! For example, while Switzerland and Turkey appear on opposite sides of the spectrum in OP, they are close to each other in the modal split. And Turkey has even much less car use than Switzerland! 61.6% vs 77.7%. Apparently, taking the bus is very common in Turkey. With 36.6% more than any other country has in train and bus combined.

And while Germany looks literally green in the upper half in OP, modal split shows it's car dependency with 85.4%.
Most people have far more km to work every day than the longer trips to visit distant relatives. Thus how often you take the train is a useful metric.

Plus someone who drives to work.already has a car so the marginal cost of the longer trip is insignificant. While someone who normally doesn't drive has to make up the costs of a car for rare trips only and that makes the marginal cost of a car very high. So people who don't drive daily are more likely to figure out how to take those long trips without a car.
- This pattern is true and passenger kilometers represent it just fine. There is no need to use the how often you use the train metric. Note that my two examples were there to explain the metric, not actual factual examples.
  
  As an actual example: I take my bike to work and dont own a car, so my modal split is mostly trains because of longer distance trips, but I use the bike far more often. Frequencies only make sense if each occurrence is very similar (in quantity). For example: How often does one eat meat? Each meal roughly contains the same amount of meat (may be factor two or three difference). Here frequencies make more sense as more detailed statistics dont actually give more insights.

I fully understand not wanting to use a train in Greece.
https://www.dw.com/en/greece-train-crash-government-admits-decades-of-failure/a-64864913

A probe into the tragedy would focus on the "chronic delays in implementing railway works, delays caused by chronic public sector malaise and decades of failure," government spokesman Yiannis Economou told reporters in Athens.

That said, I feel all European countries, maybe except of Switzerland, have failed to proper care for their rail infrastructure and missed the chance to convince more people to travel with trains instead of cars. :(

At least not in urban areas in Austria

I mean no country could afford to build a trainstation in every village
- https://en.wikipedia.org/wiki/Vatican_Railway
  
  The Vatican Railway (Italian: Ferrovia Vaticana) was opened in 1934 to serve Vatican City and its only station, Vatican City (Città del Vaticano [tʃitˈta ddel vatiˈkaːno], or Stazione Vaticana [statˈtsjoːne vatiˈkaːna]). The main rail tracks are standard gauge and 300 metres (980 ft) long, with two freight sidings, making it the shortest national railway system in the world.[1] Access to the Italian rail network is over a viaduct to Roma San Pietro railway station, and is guaranteed by the Lateran Treaty dating from 1929. The tracks and station were constructed during the reign of Pope Pius XI, shortly after the treaty.
  
  Beginning in 2015, one passenger service runs each Saturday morning with passengers for Castel Gandolfo. Most other rail traffic consists of inbound freight goods, although the railway has occasionally carried other passengers, usually for symbolic or ceremonial reasons.[2][3]
Correction: trains in Greece are no longer public sector. They are all owned by Ferrovie dello stato italiane, the failure of setting up failsafes and maintenance are because it wasn't profitable enough to do so.

Where is The Netherlands? We have loads of trains. Covid ok, but ??

I travel by train sometimes yet i've never seen a train remotely full here in my life. I've seen fuller trains going to the alpes than than those going to Amsterdam. This may be different during rush hours but outside of the rush hours trains are quite empty.
- I'm literally sitting on a train from Utrecht to ams. The previous one was so full that security needs to tell people to stop pushing. This one is also so full there are 0 free spots and the middle of the carriage is full too. Maybe it is you who don't travel by train that much over here, no?
- My experience is quite the opposite, but then again I'm always taking the train during rush hour

The Netherlands is very much missing from this

My thoughts as well. There is a ton of train commuting within the Randstad for example. My girlfriend's company has a surprising number of people who do a daily commute from Rotterdam to Amsterdam as well as places like Den Haag and Haarlem.

If you look at the stats here, The Netherlands ranks 7th nationally for % of trips taken by rail and only Austria and Switzerland are ahead of it out of western European countries.

It also ranks very highly for passenger kilometers which is saying a lot because the country is small as shit, most of the people are packed into an area about 1/3 the size of Belgium, and the overall population is fairly small when compared to places like Spain, France, Italy, and Germany.

https://en.wikipedia.org/wiki/List_of_countries_by_rail_usage
- There is a strange drop-off where train travel gets significantly worse for longer distances though.
  
  Commuting within the Randstad, and to a certain degree the provinces of Flevoland, Gelderland and Noord-Brabant is pretty compelling because the network is well connected. Need to get anywhere else though and the benefits of train travel over commuting by car start to disappear quickly.
  
  This also ties into the fact that our public transit is by far the most expensive in the EU (and possibly even worldwide). Which makes traveling by train really only a viable option if you have the money to spare or your employer covers your travel expenses.
  
  A pretty standard daily commute can cost upwards of €20 per round trip, which comes down to nearly a fifth of a minimum wage budget after taxes. That doesn't well with a housing crisis.

Feel like the title could just as easily have been “countries with the best train infrastructure”

Nah, that would be inaccurate. The country with the densest train infrastructure in the world (Czechia) is missing altogether from the image. I call bullshit.
- If bohemia is similar to Poland in that regard than that might be beacuse rail freight transport is still fairly significant

2021 has got to be a bad sample year with COVID lockdowns differing from country to country, right?

The news source has 2019 for comparison because of Covid.

https://www.euronews.com/next/2023/09/22/riding-the-rails-which-country-travels-the-most-by-train-in-europe
- Oh great! Seems like the data is at the very least comparable, although the numbers are a bit deflated.
Yeah in Belgium if I’m not mistaken I didn’t go much to the office in 2021… I think I dropped my abonnement for the train that year.

I'd use the train if we had one

Had to check which countries don't have trains in Europe. Andorra, Cyprus, Iceland, Malta and San Marino seem to be the options.
Name checks out

https://www.euronews.com/next/2023/09/22/riding-the-rails-which-country-travels-the-most-by-train-in-europe

Here's the article this image arms to be based on, which includes many more counties.

That looks like bullshit. Or it's at least missing some data. Czechia, by the very nature of being in the middle of Europe, we have the densest train network which in turn means our trains go even to the smallest of shitholes and it's very common to take a train somewhere.

This does not seem to be true. According to Wikipedia the Czech Republic has 9567 km of railways. This leaves them with a density of 0.121299336891 Railway/km².

Switzerland, which was listed as the densest in the Article, has 5317 km of railways. This leaves them with a density of 0.128787695288 Railway/km².

https://en.m.wikipedia.org/wiki/List_of_countries_by_rail_transport_network_size

Keep in mind, that the dates of the data collection are 3 years apart (Czechia 2017, Switzerland 2020).

Finland is missing

Well sure but that’s because Switzerland has a pretty awesome and geographically-appropriate-for-its-size train system.

Also, the flag’s a big plus
What does that mean? I'm not sure if I correctly interpret that as somewhat dismissive, as if a good train system was a given or not. It's the result of political will and investment.

in 2017, Germany invested €69 per citizen in its railways, ahead of France's €38 and Spain's €32. It's still far behind other countries, however, with Switzerland and Austria investing €362 and €187 per citizen respectively.

A bit like when you get Zerg rushed in Starcraft and say "Well sure but that's because they built so many units early on". It's a decision, and becoming good in that metric was precisely the intent. Also not to do so is a decision. Unlike in Starcraft, the decision to neglect your public transport is not a similarly viable strategy.
- I mean that Switzerland has a local and regional rail system that is damn near perfectly sized, scaled, and engineered for its geography and citizenry, which also integrates pretty well with the rail systems of all of its neighbors.
  
  They could have made faster trains, but with the way they wanted to run them, it made more sense to design the rolling stock to have good top speed, but excellent acceleration, thus improving the average speed more meaningfully than a higher top speed would. The rail network is fairly pervasive - you can from and to just about anywhere in Switzerland using trains, with perhaps a bit of bus travel tacked onto either end.
  
  Source: was just over there a couple months ago visiting a family friend, and used the train system a lot.

As a train traveler in Bulgaria (absent from this statistic but present in the one posted in the comments), I can vouch for our low rates of train commute (still 3 times higher than Greece) The car culture is going strong with everyone using their own vehicle. A lot of places are barely reachable by bus and unreachable by train. It takes longer and there are delays. The security is questionable with creeps causing trouble fairly often, despite police always being present. It's rather dirty, the trains are mostly Soviet era. We can't talk about air conditioning, only open windows (which you prop open with an item that you're not afraid to lose) and scorching radiators.

Despite all that I love commuting by train. I can sit comfortably, stretch, walk around, use the (very poor) toilet if needed. I can cross stitch when creeps don't try to talk to me, I try to sit around grannies that take interest at most. It's cheap, you can go from the coast to Sofia in about 7 hours for 15 euros, half if you have a card. It's easier to talk with the person I'm traveling with. The scenery of rural Bulgaria is absolutely beautiful, and best of all - No motion sickness!

My country has 0 trains.

Is the EU a country

Might be an EU average.

this seems to somewhat correlate with cold.

Also the economy to some extent which would make sense because rail infrastructure is not cheap
- I would say to a bigger extent than climate. Population density is also important.

Quite a lot of Italians use rail travel, at least that’s what it seemed to me when I was there for a few weeks. The trains and stations definitely felt a little dated, especially after I took a few Belgian trains, but they were better than anything available in the states.

We have new trains now :)

https://it.wikipedia.org/wiki/Hitachi_Rock https://it.wikipedia.org/wiki/Elettrotreno_FS_ETR.103-104

What do European country are you from?

France, Germany, EU, Sweden

All are countries in the EU

It's obviously referring to the EU average.

This is very common in European and EU graphs. In statistics with countries world wide, it's common to see "World" (and sometimes also "EU") as an entry