We have been discussing till now that we need to dig deep straight, reach the earth crust and come up exactly upwards on the opposite direction. Say, the Newzealand and Spain example which are geographically the opposite and straight if we travel through earth’s core.
But what if we never think of reaching the earth core and travel rather shorter distances. All’s well, the gravitaional force, the air pressure, the frictional forces come into much consideration when we have to ACTUALLY REACH THE EARTH’S CORE.

WHAT IS WE NEVER REACH THE EARTH’S CORE? Imagine a circle, rather than a sphere for a moment. Uptil now we have been talking about travelling as a diameter of a circle thus we reach the two extreme points of the circle. What if we consider different chords of the circle and travel from one point of the circle and reach another, much closer point not reaching the core. This will leave us of some considerations of physics be it the gravitional forces, etc.

Naturally, the gravitational force acting at the earth’s core is the maximum so we never need to consider the extreme force. Imagine a place China, if we go straight, we will land on Argentina on the other side, but we are passing the core in this way. Instead, imagine travelling from China to North America, that will make a chord in the circle have shorter distance.

Now imagine going from North America in a different tunnel straight, this will open somewhere in the Indian Ocean. Rather, imagine going to Australia from North America, this will make the 2nd chord of the circle. Now imagine the 3rd chord from Australia to China, short distance thought but just for the sake of connecting places.

If you imagine these THREE CHORDS inside earth’s sphere, you will come to realize that none of these have actualled travelled throught the earth’s core. I am no man of physics but I am sure this will create less troublesome gravity train routes, some which we might believe to be true.

Once a 15th century man thought that we might one day land on moon. People laughed at him, but our great great grand fathers and forefathers never thought we would one day be using cell phones.

It also occurred to me that rather than using magnets and/or electromagnets to reduce friction just use a cushion of gas. If i remember correctly heat can destroy magnets by rearranging the atoms but don’t quote me on that.

Yes, I know, gravity is supposed to increase toward the center of the earth, but does it and does such an idea make the slightest bit of sense.

Has no one considered that the internal and external dynamics of the earth must be inversely proportional to maintain a balanced relatively stable structure. If so gravity decreases from the surface curve to the center of the earth, just as it decreases isometrically from the surface curve.

So the whole idea of a tunnel through the earth is not a reasonable idea at all.

You only have to consider the deepest hole ever drilled which is in Siberia to see that a hole to the center of the earth is not feasible, as the energy of the earth increases with depth the drill simply stops cutting.

Of course a hole in the ground simply extends the external dynamics inward without accessing the internal dynamics which always remain on the inside.

A fun idea the gravity express, but not very realistic. But if gravity is your passion you might want to check out the 7 chapters of a book called Unity at http://www.gravitycontrol.org

Some interesting thoughts on gravity for sure.

Banmeihack, altering the pressure of your fluid is not necessary with compounds used in air conditioning and refridgeration. I think you will find this article interesting. An MIT Peace Corp student is using just your idea to provide energy for poor developing countries:
http://www.technologyreview.com/read_article.aspx?ch=biztech&sc=&id=17169&pg=2

The efficiencies touted sound impressive. Coupled with some cheap fresnel lenses, I could see how this could easily provide home energy in a small foot print (less household cooling and air heating needs). Of course thermal battery home designs could solve these problems. I’ve been working on that idea for a while now.

Personally, I’ve always liked solar. Much more so than wind or ocean power. But I’m afraid ugly fuels like nuclear, coal and oil are going to be necessary for a long time.

The recent commitiment to creating wonder crops with great caloric potential is a bit of a horror movie also. This perhaps to fuel our cars and automobiles while still keeping the traditional market forces over energy production and distributuion.

Lets hope those new crops aren’t flammable and don’t destroy too much soil.