How is a change like this going to be implemented? E.g. are they going to mainly update some tracks everywhere (and have two systems running in parallel), or all tracks in selected areas (and have passengers change), or something else?
Was there a comparable large scale rail infrastructure change in some other country?
[1] https://yle.fi/a/74-20161793
[2] https://en.wikipedia.org/wiki/Helsinki%E2%80%93Tallinn_Tunne...
The subtext is not economic: it's "in the event of being invaded by Russia, can we minimize the delays in moving NATO materiel by rail to the front while denying Russia equally easy access to the rails".
And if there isn't a war, the benefits of a interconnected and integrated european railwail network are potentially huge. 300 km/h trains connecting Finnland with Spain with no delay or bumps? That would be something.
Bit tricky this: either you cross the Baltic by ferry and resume at Tallinn, or you have to go a long way round north from Helsinki and come down again through Sweden, across Oresund and through Denmark.
https://en.wikipedia.org/wiki/%C3%98resund_Bridge
And more tunnels are getting build.
I wouldn't generalize from that to "nobody could destroy a bridge".
Moving goalposts?
"That bridge is going to be incredibly easy to destroy"
Of course bridges can be destroyed. Also Ukraine would have succeded by now, if it really would have changed the war and justify the efforts.
(It doesn't anymore, since russia has the land train connections)
But it really ain't "incredibly easy", if that bridge is guarded. The failed attempts document as much - and Ukraine knows how to destroy things by now.