as young teens me and some mates used to run across a railway bridge at night, we used to try and cut it closer each time with the trains behind us. Usually we ran all at the same time, and some of the more stupid of us would leave it a little later for the 100m odd sprint with high speed trains behind us.
Once we cut it so close that the last one jumped the last bit and grabbed the rail of the bridge, which was broken and he was hanging off this 40ft bridge. luckily he managed to swing to the path that the rest of us were at.