Providing these €49 tickets requires an annual subsidy of around €3bn, on top of already substantial subsidies for the rail industry. If we accept that it reduces carbon emissions by 6.7 million tonnes per year, then that works out to €447 per tonne. That really isn't good value - most carbon abatement methods cost well under $100 per tonne. I do recognise that modal shift towards rail may have other positive externa…
Funding road repairs, construction, and expansion from general tax revenues is similarly subsidizing a different mode of transit, and it's likely a much higher value than the 3b€ you mention (and likely more than overall railway sector subsidizing, tho I'm not familiar with Germany's budget). Also recognizing that other positive externalities exist, but pricing them at $0, seems silly.
Not trying to detract discussion, just finding it hilarious that when facing a potentially existential threat from russians who repeatedly claim they will wipe them out, they will do just about anything rather than making their military into something a bit better than an chronically underfunded joke its now.