Also tunnels would be much more expensive to maintain than simple surface railroad. When speaking about high speed rail network - there were already locomotives 50 years ago that could reach 200km/h, the problem was always track quality, reliability, maintenance cost of such high speed railway.

There is also high speed connection between Prague, Bratislava and Wien via Pendolino, although its top speed is only ~200km/h. Probably higher speed is not needed right now.

__________________
No loyalty towards the EU.

In Russia is freedom of speech. In America is also freedom after speech. -- Yakov Smirnoff