Titled link:
China's supersonic 'flying train' could travel at 2,500mph | Daily Mail Online -- it will be a vactrain.
Here are some reference speeds:
- Highway driving: 100 km/h
- High-speed train: 300 km/h
- Airliner (long-distance): 900 km/h
- Hyperloop (vactrain): 1200 km/h
- Chinese "flying train" (vactrain): 4000 km/h
- Low Earth orbit: 28,000 km/h
Numbers in mph: 62, 186, 559, 746, 2490, 17400.
I included low Earth orbit because that is the case where a vehicle's speed will provide enough lift to balance out the Earth's gravity.
A problem is how far it takes to accelerate to those speeds. If it takes more than the travel distance, the vehicle will not reach its intended speed, and if it reaches that speed, it must decelerate to stop. I'll use 1 g (9.81 m/s^2) as my reference value, since it produces a vector sum of 1.4 g 45d downward. Much more acceleration than that will get very uncomfortable. 0.3 g is more pleasant, and it adds up to about 1.04 g at an angle of 17d from vertical.
The acceleration distance is v^2/(2*g), where v is the target speed.
The resulting distances, in km: 0.0393, 0.354, 3.18, 5.66, 62.9, 3080
For acceleration and deceleration together, in km: 0.0787, 0.708, 6.37, 11.3, 126, 6170
The above, for 0.3 g, in km: 0.262, 2.36, 21.2, 37.8, 419, 20600
For China, some city distances are Beijing - Shanghai: 1069 km, Beijing - Hong Kong: 1961 km, Beijing - Chengdu: 1526 km (
Distance Calculator Find Distance Between Cities). So with the 4000 km/h version, one could do Beijing - Hong Kong in 1/2 hour with 10% or less of the distance used for accelerating and decelerating.
For the US, NYC - DC is 328 km, too short for the 4000 km/h version, though acceptable for a 1000 km/h version. That would give a time of 1/2 hour. However, NYC - Chicago is 1146 km, NYC - Dallas is 2208 km, and NYC - LA is 3940 km, far enough for a 4000 km/h version.