The new Gotthard tunnel is flat (0.25 % maximum grade from memory) and almost straight for 56 km ! With 20 km and shorter tunnels as well; it will be a flat, almost straight run from Zurich to Milan when finished :-)

Best Hopes for SBB,

Alan

The prosperity of Switzerland started with the collecting of the taxes for the crossing of the alps, so we can say that this way is very important for us..