What can i use as a ski rail?

Take a long piece of wood screw two PVC pipes into side by side from the bottom up. Put some kind of sealer in between the PVC pipes so that they don't move apart from each other. Get some support boards and put them sideways to prevent tipping of the rail. Build a ramp and have fun sliding your rail

PVC works great but can be a little tricky to split right down the center. A 2x6 will work fine by itself as long as there are no large splinter on the grinding surface. If you want a longer rail, a local scrap yard will have a piece of square stock that will work great and shouldn't be too expensive. You can even use an old straight ski and screw it to a 2x6, just make sure the heads are counter sunk. That will give you a slippery surface like a box and put an relic to good use.