Getting a saddle rail back in I have a saddle rail that has popped out. 

Does anyone know how to get it to go back in?
Your only option is judicious application of force. 

I'd find a way to clamp the saddle down with the nose up against an immovable object, then push the end of the rail forward with something until it clears the lug and can be slipped down and back into it's hole.

Using a length of 2x4 wood held somewhat like a handlebar may be effective at allowing you to push the end of the rail with enough force.