Rule Number One of working with steam locomotives:
1. No matter how hard you try, and how careful you are, OLD SH&T BREAKS. Usually at the most embarrassing moment.
Rule Two:
2. Generally speaking, steam locomotives don't love us anywhere near as much as we love them. And, they take great joy in reminding us of that.
I am proud to say I have taken out THREE cylinder heads in my time. Two from broken piston rods that cracked through the cross head key slot and one from a key that came loose, launched itself out of the crosshead, and the piston rod came loose, and the cylinder head got punched before I could get 497 shut down.