i would like to ask:-
"what is the problem in present design so that we can have a capsule that can accomodate just people"
there is vaccum in tunnel we can have even a bigger capsule
plz answer in basic terms as i am just a graduate student
Sounds really cool. I had read about this sort of concept. And a less credible idea, but intriguing anyway, drilling straight down through the earth to the other side, and using only gravity to provide the needed acceleration and deceleration.
Comment: 1g refers to acceleration rather than force. It's 9.8 meters/sec/sec, or 32 ft/sec/sec. It should take just over 3 minutes of constant 1g acceleration to reach 4000 mph (=5867 ft/sec), from a standing start.
The force required to achieve that depends on the mass of these capsules.
I would think that any small shift in the soil surrounding these tunnels would, uuh, really spoil your day, if you're a passenger.