Just 5 seconds!
For my final shot I wanted to capture the two locos as they were now coupled together. A 30 second exposure was fine as they weren't moving!!! But no! Whistles were exchanged and they began moving just a couple of seconds before the end of my exposure. Sods law.
I realise now I should have just held my hand over the open lens the moment they began moving. Oh well. I'll know next time.