This mod could help me debug issues with specialized trains that run their own routes. I can watch a train in map overview but this would be more fun, basically. It would be neat if I could pin to a specific train.
I also made a custom cutscene creator mod https://mods.factorio.com/mod/cutscene-creator, I would suggest using that one to specify a specific train to follow. Just type /cutscene and shift-click on the train you want to follow. Make sure you set the mod settings to have a high waiting time, and it will create a cutscene following the selected train :)