My latest invention is called the Gravity Train. The gravity train is a series of Lighter Than Air platforms that lift one end of a Gigantic zipline thousands of feet above the ground. Baskets are lifted up to the platform via boyency from either hot air or the compression and decompression of lighter than air gas. The Baskets / Pods / Shuttles / Capsules rise to the Air Platform Station where they are attached to a new materials zipline and dropped down the zipline to a resting station many miles away. The principle is that more energy is conserved from lifting the vehicle than from pushing it along the ground. If you push a vehicle along the ground you have to constantly fight friction, but in a gravity train friction can be harnessed to re-power a battery in the capsule.
In the above picture the left side would be a city like Covin,a California and the right side would be another city like San Bernardino, California. The Gravity Train should re-gain most of the energy lost in powering it in the form of travel and battery energy. As you can see from the picture there is a slight incline at the end of the line if there is any need to help slow the cart however the resistance from the generator should be sufficient. The cart is recycled. These stations could leap frog all around the globe.
There is also a version of the Gravity Train that uses geo-thermal energy to power the up transportation however I do not believe that drilling giant holes in the Earth would be wise. The heat from the Earth's core could be the reason life is possible creating the contrast with the sun and sapping that energy could lead to a closer demise of the Earth life system. This is evidenced by the diminishing size of life on earth as the core cools. It would be wise to power the upwards locomotion with either the above mentioned compressed gas or heat depending on which proves to be more efficient. I have not done the math.