wild_imagination

Ok i'm not sure about the snowman on the clock tower level, but I can help you with the rail slides.
So when you come up to a rail or a fallen tree/branch or certain curved slopes with the red line outlining the top. Hit A to either jump or relese your border from their speed. Next hit B this will allow you to do a railslide. When doing a railslide a little bar will appear above your characters head. You must keep the big red triangle in the green section of the bar. If the triangle goes into the red (so at either end of the bar) your character will loose it's balance. To keep the triangle in the green section you have to use the left thumbstick.
Hope this helps you :), let me know back how it goes