This is the top of the track. Ignore the water, that's for something else. The cart goes up the ramp from the right, hits the track stop, dumps magma north, then falls down a chute back to the magma loading trench. A hatch is placed a floor below that can be shut to stop and start magma pool filling by blocking the cart on its return fall. There is a 5x7x2 pool of magma below the hole, and to prevent overflow, that pressure plate will trigger the shutoff hatch.
This is my magma and separate water disposal system. (
ALWAYS BUILD LIQUID DISPOSAL SYSTEMS FIRST!) Do not open both at once. Water flowing to the edge makes all water connected into a "river" that counts for making all water "moving" for waterwheel purposes,
even after access to the edge is removed, removing the need for FPS-draining pumps for large water wheel operations. Those are fortifications liquids can flow through on the South edge of the map.
The cart falls down a 108-z-level shaft to...
This track. Ramps send the cart to a ditch filled with magma. The wall prevents skipping. Upon being loaded with magma, it is pushed up a ramp, given a boost with "impulse ramps" and pushed up a spiraling impulse elevator
as seen in the wiki.
In this trench is a straightaway (with ramps, obviously) with rollers of magma-safe materials set to the lowest setting, because the cart must move slowly to fill with magma, and a cart on a roller is immune to rolling back down the hill. The rollers receive power from the magma-safe pump pumping from an iron grate over the magma sea. A separate water wheel and pump with water taken from an aquifer down a 114-z channel provide power. The bridge in the bottom-left is an atom smasher for draining the water, while to the right of the magma trench is an atom-smasher for draining the magma trench.
This is my impulse elevator, running on impulse ramps. Without ramps, tracks look like this:
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I don't recommend copying my exact design. It turns out, after making it, I would have been better served with a 4x4 impulse elevator (for the fastest, no-collision carts) or a 2x2 impulse elevator (for the least digging). As this stands, the cart has collisions and goes up slowly, although predictably enough IF there is no following cart close enough to it. A 4x4 elevator does not have this problem, and can send a cart directly uphill.
To the immediate left of the impulse elevator is the cart return shaft, 108-zs of channeling. I had to make a few exits into the impulse elevator, as miners would need breaks while channeling themselves down, roughly every 5zs. It's probably better just to have a up/down stair along the shaft, I don't think the carts will ever fly sideways.
Up and to the left, is another channel and up/down stair, this one for allowing water from the aquifer down to the waterwheel chamber that powers the rollers and magma pump.