Yeah, this scenario is a bit buggy. After cloning the scenario to swap the power because it was infuriatingly bad to operate. I ended up stuck at that point because they failed to make it a unload rule, rather they ask the player to load something where it can't be loaded.
trev123 wrote:Here is another strange twist to this scenario. I was going to empty the coal wagons again at this siding starting from a resume as I have saved it here to get a screenshot of the academy error message and unloaded two of the four wagons when a message popped up saying something like great work now proceed to Gold Quarry Siding 1 and drop off the four coal wagons no mention of filling them up with shingle, so I went to the siding and uncoupled them and got a message saying now continue back to Rockwell and couple to the wagons there which is about 9 miles away. This is totally screwed.

The scenario is 130 minutes long at best, as the second half of the scenario is to retrieve those 12 cars you initially dropped off and push them to the same quarry to be loaded. Then retrieve the coal cars again and return home. However, In the grand scheme of things, there was no need to make this cut, as the consist was properly made up for shoving to the quarry.
DTG could have massively sped up and simplified the scenario by placing a caboose on the consist, flip the engine and caboose on the ends to begin, and shove to the quarry. Or place engines on either end for push pull operation. But then it wouldn't be a
"challenge"