Apparently, leaves that fall on the track are a significant issue that can cause derailments since they can turn into a lubricant when squished according to Forbes. I wouldn’t be surprised if turtles did the same (but don’t quote me on that)
With that said, the only thing I’ve actually found involving turtles are them getting stuck in switches
Not totally sure about that 2nd claim, but this is nice to see. (startrek.website)