Serendipity sometimes is in your corner. I did two sessions of engagement photos with Heather and Kenneth. About 600 frames in all. I quickly breezed through them and then gave them to the family to choose some for printing and display at the wedding. While we were shooting, a train went by and they wanted to pose watching the train. I was firing away and didn't notice the actual cars passing by. Imagine my surprise when this was one of the chosen. I didn't look carefully enough at them beforehand to notice what was on the side of the train. Lucky shot!