This picture shows the Hallerbach Valley Bridge and its 4% grade. The curve in background has a radius of 2.17 miles.

In order to reduce tunnel and bridge mileage, the 186 mph line from Köln to Frankfurt has been built steep and curvy: Up to 4% of grade, down to 2.08 miles of curve radius, up to 6.7 inches of superelevation. By German regulations, the unbalanced superelevation limit for normal, non-tilting trains is 5.9 inches.

© DB ProjektBau GmbH / Lothar Mantel, used with permission.

Unit conversion for text on this page.
186 mph 300 km/h  
2.08 miles 3350 m  
6.7 inches 170 mm  
5.9 inches of unbalanced superelevation 150 mm of unbalanced superelevation 1 m/s2 unbalanced lateral acceleration