Finnish construction workers hammer away at a project that would smooth the connections from NATO’s Atlantic shoreline in Norway to its new frontier with Russia, high above a railway bridge over a foaming river far beyond the Arctic Circle.

“We’ll be removing about 1,200 of these one at a time,” site manager Mika Hakkarainen adds, holding out a rivet.

Until February 2022, the 37-million-euro ($41-million) electrification of this small piece of track – Sweden’s only rail link to Finland – just offered inhabitants the possibility to ride a night train down to the dazzling lights of Stockholm.

After Russia invaded Ukraine, that changed.

Now Finland is part of NATO, and Sweden hopes to join soon.

As the alliance reshapes its strategy in response to Russia’s campaign, access to these new territories and their infrastructure opens ways for allies to watch and contain Moscow, and an unprecedented chance to treat the whole of northwest Europe as one bloc, nearly two dozen diplomats and military and security experts told Reuters.