
BUt assuming no HSCD (Hot swedish chick drag) they'd accelerate to maximum velocity at about half (?) depth, decelerate to zero at the center - but because of momentum keep on rocking, acelerating again to max at 3/4 but (I think) still arrive at zero speed in my garden. The only problems now are:
1) They'd probably get a bit more of a tan than is good for them (and you know how fair skinned they all are)
2) It would take a bit longer for them to show up.
The curve at the bottom is going to be a problem though. Definitely need runners, or capsules or a big water slide type thing.
Maybe I should just use it for air conditioning after all and move to the 'Tall australian blonde de-atomizing transport bay' I've back burnered recently.
EDIT: Found this: hyperphysics.phy-astr.gsu.edu/Hbase/mechanics/earthole.html
It would take 42 minutes for Helga to reach me, and she'd reach a max velocity of 17,700 mph. Glad to see other people waste days at work too.