Why people float inside free falling airplane

[hackhard]

suppose a train travels along equator at 15,600 mph in direction of rotation of Earth gforce on man inside train is 0.
2.5 times speed of rocket sled
https://en.wikipedia.org/wiki/Rocket_sled
20 times speed of hyperloop pod
https://en.wikipedia.org/wiki/Hyperloop

 

[A.T.]

suppose a train travels along equator at 15,600 mph in direction of rotation of Earth gforce on man inside train is 0.

Going into low orbit is simpler.

 

[georgir]

Going into low orbit is simpler.

It actually seems to be the same thing by definition...
Meaning simply that hackhard's train would need no rails aside from the part where it's picking up its speed initially. After that, it is technically in (very) low orbit.
[edit: in practice a way to remove atmospheric drag would be required, which still means probably a vacuum guide tunnel and the maglev equivalent of rails.]
[edit 2: which is probably more complicated than going into a not-so-low low orbit, which finally makes me appreciate the point you were probably making :p]