grades on curves

[daniel1967]

I'm constructing a point to point line (into tunnels) with a lower level mainline creating a continuous run. What materials/methods are most effective in creating a stable base on a wide radius curve with app.2.5 to 3.5 % grade between levels? I plan on making the upper level the main benchwork with a lower level shelf. Dan

[Anonymous]

It's called a helix and you can look it up on the search bar above for lots of ways to build them. FRED