3 ms·

> Superconducting maglev would be a win for acceleration/deceleration as well This limitation isn't at all technological. You just can't accelerate or decelera

> Superconducting maglev would be a win for acceleration/deceleration as well This limitation isn't at all technological. You just can't accelerate or decelerate much faster than today's high speed trains without causing discomfort to your passengers. And the radius of any turn increases with speed. Otherwise first you just produce noticeable discomfort while turning, and beyond that you risk derailment (no matter the rail type). So you're basically stuck with having really long and very straight stretches of rail where you have to gently accelerate and decelerate. On any short trip this would kill any economy of high top speed. > I kind of feel that in general it'd be better to replace planes with trains The advantage of flight is that you are free to take a more or less straight path between the 2 points without caring about what's below. But with any kind of land transportation you need to deal with rivers, mountains, lakes and seas (not to mention oceans), cities and other man made structures, etc. Without a breakthrough in engineering I don't see how you can go from London to Los Angeles in a reasonable time.

mncharity 8y ago
> This limitation isn't at all technological. You just can't accelerate or decelerate much faster than today's high speed trains without causing discomfort to your passengers. Will electric cars change people's comfort with longitudinal acceleration? Imagine people's family SUV does 0-60 at 5 m/s^2 (Tesla Model Y), and sedan around 10 m/s^2 (Model 3 and S). Then subway's ~1 m/s^2, shinkansen's 1.2, or TGV's 0.5, may seem very last century. A generic Honda Civic looks about 3.
- close04 8y ago
  We can do it but it won't be comfortable. It would be "roller coaster fun" (similar acceleration). You have 500 people on a train (half of them facing backwards) and want to give them a comfortable ride. Including keeping the coffee in their cups or their stomachs :). Again, it's not a technological challenge, it's a biological one. The human body doesn't evolve faster because we have capable cars. At 5m/s^2 we're talking ~0.5G, more than what you feel in a plane taking off (normally ~0.4G) and one order of magnitude higher than most high-speed trains accelerating (~0.03-0.05G). This is not a normal or comfortable regime. And at 0.2G lateral acceleration (in curves) you have a good chance of seeing your lunch again. This means at 600Km/h you need 15-20Km turn radius. Add to that the air turbulence at close to and over 500Km/h at sea level which causes a rumble that's nausea inducing for most people (riding in low pressure tubes may help here). Just a few other numbers for reference: Shinkansen: 0.07G ICE (German HSR): 0.05G S-Bahn (metro transport): 0.1G Plane take off: 0.4G Roller coaster: 0.5G
- scatters 8y ago
  People don't expect to be able to get work done in a passenger car. Train passengers (especially the lucrative business sector) expect their laptops to stay on the table. Another factor - half of all train passengers are facing backwards.

mncharity 8y ago

> This limitation isn't at all technological. You just can't accelerate or decelerate much faster than today's high speed trains without causing discomfort to your passengers. Will electric cars change people's comfort with longitudinal acceleration? Imagine people's family SUV does 0-60 at 5 m/s^2 (Tesla Model Y), and sedan around 10 m/s^2 (Model 3 and S). Then subway's ~1 m/s^2, shinkansen's 1.2, or TGV's 0.5, may seem very last century. A generic Honda Civic looks about 3.

close04 8y ago
We can do it but it won't be comfortable. It would be "roller coaster fun" (similar acceleration). You have 500 people on a train (half of them facing backwards) and want to give them a comfortable ride. Including keeping the coffee in their cups or their stomachs :). Again, it's not a technological challenge, it's a biological one. The human body doesn't evolve faster because we have capable cars. At 5m/s^2 we're talking ~0.5G, more than what you feel in a plane taking off (normally ~0.4G) and one order of magnitude higher than most high-speed trains accelerating (~0.03-0.05G). This is not a normal or comfortable regime. And at 0.2G lateral acceleration (in curves) you have a good chance of seeing your lunch again. This means at 600Km/h you need 15-20Km turn radius. Add to that the air turbulence at close to and over 500Km/h at sea level which causes a rumble that's nausea inducing for most people (riding in low pressure tubes may help here). Just a few other numbers for reference: Shinkansen: 0.07G ICE (German HSR): 0.05G S-Bahn (metro transport): 0.1G Plane take off: 0.4G Roller coaster: 0.5G
scatters 8y ago
People don't expect to be able to get work done in a passenger car. Train passengers (especially the lucrative business sector) expect their laptops to stay on the table. Another factor - half of all train passengers are facing backwards.