Two part: The steam pipe venting along side the stack is I believe the exhaust from the air pumps. Common practice is usually to vent it into the smokebox under the petticoat to help induce draft. I have noticed that on 19, you can get down to a spot fire sometimes that is practically sucked out by the draft induced by the air pump when for instance you are standing at the depot charging the train line and the air pump runs pretty fast. They might have been trying to avoid this.
Second thing is I have seen photo(s) of the S.Baker fueling set up. It was a horizontal tank car tank like in the Mexican photo, but with a building around it. Maybe Ron Brinton can help in terms of posting a photo of this. Somebody has said that the old tank car tank that is at the McEwen yard next to the restoraton shop is that tank from S.Baker. Not sure if this is acurate. The large yellow tank down at that end of our yard may be the 99 tank car tank and may have been the oil fuel tank used at Bates. Much conjecture on all of this.