I'm getting my Canadian real life pictures put back on the web. Here are some that may provide ideas for modelling
Winniandy (Grande Cache) is unique in that, although they have a coal mine and a power station alongside each other, the coal that is mined there is taken for export (usually via Roberts Bank in Vancouver) while the power station gets its coal sent in from a different location. The cars bringing the coal in to the power station are made of steel and are different to the aluminium cars used to export the coal.
You can therefore have empty and fully loaded coal cars going in both directions.
Enjoy