The World's longest railway tunnel, Gotthard Base Tunnel is featured in a CNN article. It is surprisingly elaborate article as you would not expect from a mainstream publication. There are one or a few mistakes (one being `the Gotthard Base tunnel construction is almost finished` - as far as I know, it is already finished in 2016).

I liked this:

Excavation on this scale generated extraordinary quantities of rock and spoil; the rock from the Gotthard tunnels alone would have filled a train of wagons stretching from Zurich to Chicago -- a distance of 4,440 miles.

It is interesting to read this from CNN:

https://edition.cnn.com/travel/article/trans-alpine-rail-tunnels/index.html