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Keywords from Image Description:
PfaffensprungSpiralTunnel DoubleLoopCurvedAlignmentTunnels atWassen onNorthernRampToGotthardTunnel. Summary en Outline of the Pfaffensprung spiral tunnel and the double loop at Wassen on the northern ramp to the Gotthard tunnel de PfaffensprungKehrtunnel und Linienentwicklung bei Wassen Gotthardbahn in Rll Freiherr von Enzyklopdie