We’re deep inside Switzerland’s Alps; only thick armoured glass separates us from the track. Hundreds of metres beneath sleepy Bristen, the viewing window feels cosily warm, like a kitchen oven door.

We hear the northbound Milan to Basel EuroCity before we see it hurtling towards us at over 200 kph. Then, roaring, headlamps dazzling, it blasts past just inches away. Moments later, the carriages’ ephemeral brightness has passed. The spartan concrete tube of the Gotthard Base Tunnel – the world’s longest – is silent again.

Like venturing atop Sydney’s iconic Harbour Bridge or going backstage at a major airport, exploring the 57 km-long, 12 billion Swiss Francs tunnel was a spectacular, special privilege.

Very ‘James Bond’

Earlier, leaving Erstfeld, we’d driven south along the Reuss Valley in the central Swiss canton of Uri. At Amsteg, leaving holiday traffic behind, we turned off the cantonal road and entered a modest concrete portal in the valleyside. It all felt very ‘James Bond’ as we drove two kilometres along the Amsteg ‘Zugangsstollen’ – an access tunnel dating from the tunnel’s construction.

Eventually, we stopped, donned hi-viz vests and helmets, and walked. For 90 minutes, watched over by St. Barbara, patron saint of tunnellers, we learned about the challenges facing tunnel builders during 17 years of planning and construction. Our guide, local project manager Charly Simmen, had worked on the project, knew it intimately and impressed with his knowledge of a structure I’d often used, since its opening in 2016.

As Charly described the project’s four massive Herrenknecht boring machines, mind-blowing logistics and confounding geology, the breathtaking facts kept coming. The geological challenges ranged from tough granite to nightmarish sugar-like Piora-Mulde.

During tunnelling, temperatures in the mountain reached 50°C and 2,400 workers built hundreds of kilometres of tunnels, tracks and cabling with stunning precision. They extracted 28.2 million tonnes of rock too – and discovered Amstegite, a previously unrecorded mineral. Like the original Gotthard summit tunnel in 1882, it was Switzerland’s project of the century!

A rail enthusiast’s dream

Visiting was a rail enthusiast’s dream. Later, back in the fresh air, I reflected on how this engineering masterpiece revolutionised trans-Alpine rail traffic, shortened journey times and took hundreds of trains off the original Gotthard railway every day.

Leaving Erstfeld station, one final surprise awaited. As I walked past, one of Gotthard’s iconic vintage ‘Krokodil’ locos – mainstays of the original mountain line for decades – poked its iconic brown snout from a shed. In one morning, I realised, I’d seen the inspiring future and unforgettable past of trans-Gotthard rail travel!