Service 0Z31 using the class 66 to load empty ballast wagons, there is no instruction on the loading procedure. The only direction given is to "go via" the loading facility. It does not tell you to move through the loading facility at a low speed, so that you can successfully load the wagons. There is also no instruction on how to use the slow speed control, like there is on GWR "Aggregate industries" or in the coal loading scenarios in Tees Valley Line. Additionally you are placed in the rear No2 cab, which is facing the wrong way for the task of loading/moving turning around. If this was the first TSW game that someone has bought, they wouldn't necessarily know that this was the objective of the scenario, or that you need to move through the loader at a sufficiently low speed.
They mentioned making objectives more clear as a feature in TSW2- it's sorely needed in some cases like this. It's weird though because some are well written and easy to follow, and others are really vague. Hopefully we'll see some more consistency in the future.