Step 1: SCOPE THE RAIL.
A kinked rail starts out sloping downward, angles up, and slides down again. Think about your bases in relation to the angles. The key is to stay flat on the rail at all times.
Step 2: SUCK IT UP.
When you hit the first kink, suck your skis up toward your stomach (just slightly) and move your feet out in front of you so your bases—not your edges—stay on the rail. Metal against metal will leave you sprawled on the ground.
Step 3: FOCUS AHEAD OF THE KINK.
Try not to focus all your attention on the kink. Look past it to the next "down section of the rail. Make it to here and you're almost home free.
Step 4: STAY RELAXED.
Keep your weight slightly forward so you can slide the last down section with your bases flat. Once you're comfortable with the kink, try going switch or jumping and clearing the final down portion.
Get aggressive. You will bruise big-time if you try to pussyfoot onto the rail.