I'm sure this isn't the first time it has been mentioned but it would be extremely useful if train departure times could be to the nearest minute, rather than 5 min slots. I have an interesting scenario with lots of activity on the Tees Valley line and would like my player train to be delayed by a consist leaving Lackenby just ahead of me. If I use say 12:35 for it's departure it causes me to be stuck behind another two trains in front of me so I don't get to see the steel train join the main line. Make it 12:40 and I am liable to get there in time to gain dispatcher priority and sail through on a green. In many scenarios there's a sweet spot for the AI timings and one minute intervals would be a huge improvement.
