Why Amtrak trains will stay slower

+ an important conclusion

Looking at the last 10 pages, it's now time for a summary, which curve speeds might be achievable under the operating conditions in the USA.

For a translation into practical implications, the following table gives examples of speed results for a given radius. Passenger priority track and freight track is compared to the maximum, that is currently allowed in Europe:

curve radius max. legal limit, Europe expected for passenger track, USA expected for freight track, USA
800 feet (244m) 62 mph (100 km/h) 55 mph (89 km/h) 45 mph (72 km/h)
1600 feet (488m) 88 mph (141 km/h) 78 mph (125 km/h) 64 mph (102 km/h)
The assumptions for this table:
Maximum legal limit in Europe: 7.1 inches (180mm) superelevation, 11.8 inches (300mm) cant deficiency
Passenger track, USA: 6 inches (152mm) superelevation, 9 inches (229mm) cant deficiency
Freight track, USA: 3 inches (76mm) superelevation, 7 inches (178mm) cant deficiency

While the figures look low in comparison to possibilities, they are higher than for any current operation in the USA. They mark the limit of what is achievable under current circumstances, and will be used as assumptions for the rest of this article.

An inportant conclusion out of these figures needs to be noted: European tilting DMUs normally operate on mixed-usage track. In the USA, different operating conditions would make tilting trains much faster on dedicated track, or on track for passenger traffic plus a low amount of freight.

Unit conversion for text on this page.
11.8 inches of cant deficiency 300 mm of cant deficiency 2 m/s2 unbalanced lateral acceleration
9 inches of cant deficiency 229 mm of cant deficiency 1.51 m/s2 unbalanced lateral acceleration
10 inches of cant deficiency 254 mm of cant deficiency 1.68 m/s2 unbalanced lateral acceleration
7 inches of cant deficiency 178 mm of cant deficiency 1.17 m/s2 unbalanced lateral acceleration
8 inches of cant deficiency 203 mm of cant deficiency 1.34 m/s2 unbalanced lateral acceleration
6 inches 152 mm  
3 inches 76 mm  
4 inches 102 mm  
  800 feet (244m) radius 7 degrees 10 minutes of curvature
  1600 feet (488m) radius 3 degrees 35 minutes of curvature

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Last modified: 2005-04-16