There's a great 360° video on Youtube that shows both the tunnel as well as the Gotthard massif through which the tunnel leads. It's in German, but the visuals are impressive on their own.
OMG I just understood what you meant with 360! You can swipe to the direction you want, like in Quicktime VR, but animated! I didn't know Youtube made it possible! The video was just showing the rails, I thought it was boring until I understood the concept.
Make sure to open it on your mobile or tablet. You can pan around physically with your device, which makes it quite immersive (more so if you have a VR device, of course).
If you've got a recent-ish smartphone, I would highly recommend getting yourself a Google Cardboard for watching YouTube 360 videos, it really makes it even cooler. Yeah it's "poor man's VR" and certainly not in the same league as things like the Rift/Vive, but it's 15 bucks, so why not? I definitely feel like I've gotten 15 bucks worth of use out of mine, mostly because of videos like this.
I'm afraid that train has left the station (sorry for the pun). All the construction infrastructure is gone, and in half a year, there will be hundreds of trains thundering through the tunnel every day. The Porta Alpina was economically questionable to begin with, but now it would just be non-sensical.
(Saying this as someone from a region that would have had an immense benefit of the Porta Alpina station)
Porta Alpina ("Alpine Gate") was a proposed railway station to be located in the middle of the Gotthard Base Tunnel in southern Switzerland. Intended to promote tourism and the economy in the region of Graubünden, the project was put on hold as uneconomical in 2007, and then indefinitely shelved by the Swiss authorities in 2012.
Porta Alpina would have been the deepest underground train station in the world at 800 metres underground, outclassing by far Arsenalna Metro station at 105.5 metres.
The station was proposed to be located near a crossover between the northbound and southbound tunnels and to be linked to the surface by the world's highest elevator, using shafts built near the village of Sedrun for the construction of the tunnel. Construction costs were estimated at 40-50 million Swiss francs, with annual operating costs of 2.5 million francs. It was initially projected to be opened in 2016 after the Base Tunnel was scheduled to come into service.
https://www.youtube.com/watch?v=qDSCtXvL51o