In addition to the other replies, I want to point out that a major reason for the tunnel's existence isn't just to reduce travel times, but to provide an alternative way for freight to cross the mountains besides using trucks over the roads, which are dangerous and make a lot more pollution. Even if transit times for passengers don't decrease that much, this will be judged a success if it gets a lot of freight trucks off the road.
It cuts the Zürich-Milan journey time for passenger trains by about an hour (from 173 to 111 minutes) accelerating train trips from Germany/Switzerland to Italy significantly.
I don't get this. Zurich is in Switzerland. I don't think even with this tunnel opening we will be getting from Zurich to Milan in under 2 hours... Are your numbers wrong?
Edit: we will be looking at journey times of about 170 minutes from Zurich to Milan AFTER the tunnel opens.
Self-correction: It cuts the Zürich-Lugano journey time from 173 to 111 minutes rather than Zürich-Milan (which still takes longer). Though it does cut journey times for the latter by an hour too.