I run 6 miles every other day. A local rails-to-trails path near me is exactly 2.5 miles long, so I have to find some way of getting in an extra mile on my runs. The trail ends at a real railroad track, so for a while I tried running a half mile on the track and back, between the rails landing on every other tie as I ran since the distance perfectly matched my stride. This went on for a couple of years until one day I was doing it and actually started thinking "wow, this is pretty amazing that I can do this and not fall". Not five seconds later I tripped and fell, landing both elbows and both knees on tie.

Somehow I was only bruised and didn't break anything, and after ten minutes of groaning I was able to drag myself up and even complete my run. That was my last time running on railroad ties though.