The Germans realised the strategic importance of the viaduct and decided to build a 'viaduct by-pass'. On December 1st 1944 the Todt Organisation began the construction of a single track line using mostly slave labourers from occupied countries.
The by-pass was 3.4 km long and because of the tight curves and steep gradients the maximum speed of a train was restricted to 50km/h. Additional locomotives had to be on permanent standby to help heavy goods trains that might need an 'extra push'.
The line was so shaky that it was named the "Gummibahn" or "Rubber Railway".
It remains something of a military intelligence puzzle why so much effort was expended in destroying the viaducts later in the war when it was known that an easily repairable alternative was already in existence.
Today, no trace whatsoever remains of the 'Gummibahn'.