It is ok for those people who just want to know if there is a rail line from A to B but it lacks detail as its a tourist map. If you want detail then this is the Atlas https://europeanrailwayatlas.com/about-the-european-railway-atlas/ This is a link to sample pages from different countries - https://europeanrailwayatlas.com/wp-content/uploads/ERA_Sample_2023.pdf
in bookform you can get some further specific maps with some details "Schweers & Wall Eisenbahnatlas", available for germany (gets regulary new editions), austria, switzerland (there is a new edition planned since some years), Greece, North France (sadly no South France), and there was some years ago a european version too but with relativ small scale comparing to others. For Britain there is "Trackatlas of Mainland Britain" (A comprehensice Geographic Atlas Showing the Rail Network of Great Britiain), by Mike Bridge
