Solkan Bridge: the largest stone arch railway bridge in the world, and why it's worth the detour

Just outside Nova Gorica, where the railway from Bohinj finally comes down out of the mountains, it crosses the Soča on a single stone arch 85 metres wide – the largest stone arch railway bridge anywhere in the world, and still in daily use well over a century after it was built.

Why a stone arch, and why this big

The bridge was built between 1900 and 1905 as part of the same Transalpina line that tunnels under the Alps to Bohinjska Bistrica – the line the car-train still runs on today. Engineers needed to cross the Soča gorge without a pier in the riverbed, and the solution was a single arch rather than several smaller ones: 85 metres of span, carved from local stone and assembled without steel reinforcement, the way a Roman aqueduct is built rather than the way a modern bridge is.

It didn't survive the century undamaged. Retreating Austro-Hungarian forces blew up the central arch in 1916, during the Isonzo fighting that ran through this exact valley, and the bridge stood broken for over a decade. It was rebuilt stone for stone and reopened in 1927, and that is the bridge still standing – a First World War wound that healed rather than a replacement.

Where to actually see it

The classic view is from the small park just below the bridge on the Solkan side, where the full arch is visible against the gorge wall and, with some patience, a train crossing it. It is a two-minute walk from where a car can stop, not a hike – this is a quick detour, not a destination that needs an afternoon.

How it fits into a day

Solkan sits right at Nova Gorica, which puts the bridge naturally on the way between the Soča valley and the Vipava wine region or the Italian border crossing at Gorizia – a five-minute stop added to a longer transfer rather than a trip in its own right. It also sits at the far end of the same line the Bohinj car-train crosses the mountains on, so a day built around the car-train can take in the bridge at the other end of the same railway.

That is the fare for a dedicated transfer to Nova Gorica. As a stop added to a Soča valley or Vipava day it costs little beyond the few minutes spent at the viewpoint – worth mentioning when you book if it's somewhere you'd like to see.