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.
BTW Make sure to open the video in Chrome or Opera, the 360 thing does not work in Firefox
(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.