For what it's worth, Earth's "Terrasphere" is "what's deep under your feet. It's different than the BIOSPHERE where just about all life exists. When we talk about the terrasphere, we are talking about the planet. We're talking about what's beneath the surface of the Earth. There are rivers of molten rock, huge spheres of solid Iron, and more rivers, but of molten Iron. So much going on just beneath the surface."
http://www.cartage.org.lb/en/kids/science/Geog/Earth/Earth.htm
So maybe a "Terra Coaster" is a coaster, as stated above, that's close to the ground.