For any similar future event they probably need to make it pre-book only.
It isn't the answer.
Also on board the trains because it was standing room only , there were lots of people saying they couldn't buy a ticket & had no intention of buying one because of the experience, so lots of revenue was lost.
Only got themselves to blame for that - no tickets for sale at Peterborough station was not very clever. The answer would be a TTI or two doing sales at the station for the first part of the day. I do hope those who had no intention of buying but still attended are happy to look themselves in the mirror - it's pretty disgusting (and downright dishonest) to do that for a charity event.
The fundamental issue with the overcrowding was that they could only run one train at a time between Wansford and Peterborough, which meant the timetable had half the capacity it could have done. For what it's worth, I'd suggest:
1. Ditch the Fletton shuttles and run a Yarwell shuttle instead. This stuffed capacity as trains couldn't pass at Orton Mere.
2. Have trains pass at Orton Mere. I know there is a platform issue on one side that prevents longer trains calling - if needs be have them not stopping in one direction.
3. Use air brake stock. The timetable collapse was at least partly down to the running round of the Peak on the vac brake set. It adds time and risk. There is another air brake set on the railway but chose not to use it.
Doing that you address the capacity issues and take out a performance risk.