The closest U-Bahn train station is Nürnberg Bärenschanze) — 5 stops / 7 minutes from the Hauptbahnhof (Main Station). Metro line U1 runs up to ten times per hour and stops amongst others in the old town area at the Lorenzkirche and Weißer Turm U-Bahn stations.
It is a five-minute walk from the Bärenschanze station to the Memorial — signposting is clear but it is basically a long block along Fürther Straße and turn right.