Mars Railroad, a Stem Design Exercise

I put this out to the world-wide stem community as a challenge. Design a viable railroad for Mars. Get a viable Mars-based railroad defined. We are going to need it. It will take a while. Start now.When humans arrive on Mars, and for a while afterwards, they will be completely dependent of periodic resupply missions from Earth. They will need to find their own supplies, chiefly water and methane, later minerals and metals. Mars will be in the pre-Industrial Revolution phase, Just like when the early American settlers were dependent on resupply ships from Europe. Excpet the early American settlers found abundant food and indigenous people. Railroading on Mars. This has not been done. It will be done eventually by someone. Why not you?