Con el tren

• West railway station "Westbahnhof"
  Just take tram 52 or 58 1 stop until "Staglgasse"

• South railway station "Südbahnhof"
  Take tram 18 (direct without changing line) in direction to "Burgasse/Stadthalle", and get out at station "Westbahnhof".
  
  Useful links:

Schedul of Austrian Federal Railways

Schedule of German Federal Railways