Saving time is only a small part of it, it is also because they want to have 10 on hand to run the excursions in case of any more issues with 17, and to have 10 ready to haul the regularly scheduled diesel powered excursions, which are done for the year.
I was fully expecting the cyclists to group together across the tracks in front of the train and impede it’s progress, then angrily flip off the engineer for blowing the wistle! 😂😂