That is actually why I crashed. I usually ride in the streets but considering my inebriated state I figured I would try to avoid playing with traffic. So I was coming down the sidewalk approaching some train tracks that cross the sidewalk at about 20-30 degrees (from parallel) and as soon as my front tire hits the tracks it slides out and im down...

I've gone over these tracks numerous time on the road and never had a problem but apparently the sidewalk leaves enough room for my tire to get stuck.... damn train tracks