Replying to How Do I Build a Rail to Practice on This Summer???

I want to build a rail to practice this summer. I know how to make the ramp and what surface to use. But I do not know how to build the rail. I can't have anything permanent like in the ground. I was thinking I would get a 6x6 and attach some metal pipes on the top of the sides. Then to stop it from tipping it over I would attach the 6x6 to a couple pieces of plywood. This was my first season skiing so I don't know how long it should be or how high the rail needs to be so that I don't hit my skis on the ground if I try a switch up. Any suggestions?