The I5 Tejon Pass goes up to an altitude of 1.2km with a 6% section [1]. From a quick search, it appears that the steepest gradients in France/Germany and Japan

The I5 Tejon Pass goes up to an altitude of 1.2km with a 6% section [1]. From a quick search, it appears that the steepest gradients in France/Germany and Japan's Shinkansen are 4% [2]. I'm not certain about China but it appears that the HSR to Kunming (1.9km altitude) has a limiting gradient of 2.3% [3]. Maybe they could solve it with clever engineering. However, I don't think 20 minutes is a big deal, especially considering that the Japanese have put up with the humiliation of spending 2:21 instead of 1:07 to go from Tokyo to Osaka for the last few decades. I think focusing on only SF-LA also ignores long-term goals, like connecting with the Brightline from Victorville to Las Vegas. If you live in Fresno or Bakersfield and want to go to Las Vegas, your options are pretty ridiculously long bus rides, or long multi-legged flights. If both the CA HSR and Brightline succeed (I know, I'm hopeless optimistic), then it can be a pretty killer app. * [1] https://www.dangerousroads.org/north-america/usa/4366-tejon-pass.html https://www.dangerousroads.org/north-america/usa/4366-tejon-... * [2] https://en.wikipedia.org/wiki/List_of_steepest_gradients_on_adhesion_railways https://en.wikipedia.org/wiki/List_of_steepest_gradients_on_... * [3] [Note that the gradient here is listed as per-mille] https://en.wikipedia.org/wiki/Nanning%E2%80%93Kunming_high-speed_railway https://en.wikipedia.org/wiki/Nanning%E2%80%93Kunming_high-s...