This was an interesting experience! Sitting in a Glasgow underground train station, I had my camera and tripod set up, when a Police officer approaches me. After reading all the bad stories, I wasn't sure what to expect here. She started questioning me about what I was doing, but I realised it was more out of curiosity. She then took an interest and even kept a waiting passenger out of my way! I thought I would keep her in the shot as a wee dedication to her. Lesson learned; be polite, don't start reeling off rights and rules, and most importantly, smile. She boarded the train sad that she couldn't see the final result. Remember people, the cops are here to help! 

As for the shot, the station itself isn't symmetrical, which will bring out the OCD in many. It's also a combination of two shots, as the trains never came along at the same time.