Problem illustration:
SNCF and Amtrak operation compared
Two trains are pictured here: A non-tilting, standard TGV of the French SNCF, and the tilting train Amtrak Cascades.
Question: If both trains run through the same tight curve, which one is faster?
TGV at La Napoule (Cote d'Azur), Cascades Talgo at Richmond Beach
Answer:
curve radius | superelevation | speed limit 1 |
|
---|---|---|---|
Cascades Talgo, tilting | 1000 feet | 4 inches | 48 mph |
TGV, non-tilting | 1000 feet | 4 inches | 53 mph |
Reason: Not the tilting mechanism sets the curve speed, but the allowed amount of unbalanced superelevation.