I took part in a big action to clean up self intersecting ways in Germany/Switzerland/Austria. Two of my tasks involved summer toboggan runs where the mapper had not used bridges for loops. Actually it's easy to know that the track always runs on a bridge first and under the bridge second. But since I tried to verify the whole track I looked for images or videos. I found both on Youtube and the second (Hasenkopf Coaster in Todtnau, Black Forest) is really long - almost 4 minutes. It was fun to watch the video and follow the track on the map.