Oil or Coal

A number of years ago, the EPA showed up at the Loop, prompted by complaints by locals regarding all the nasty smoke that was created by the train.
The train passed with no difficulty, and the EPA was also pleased with the fact that they were burning waste oil. Additionally, the railroad has facilities for loading oil, and none for loading coal.
If coal is chosen, will they get rid of the oil burner they are currently using? What about the diesel?
So for ease of operation, oil would be the choice. For historic preservation, coal.
So the precident has already been set. Question is, will they attempt to set a new precident, in the name of historic preservation, or will they try to make money running a railroad?