"While I am sounding off on brake components I have one more question. I have an Intermountain model of a Santa Fe Ga-55 65 foot gondola."
Intermountain did a 65 ft gon? That's news to me. Sounds like this is really the Athearn model.
"It is a pretty good model as is but I notice one anomaly. The brake reservoir is mounted parallel to the center sill as opposed to the standard Santa Fe practice of mounting it perpendicular to the sill. I have a drawing from a 1950’s Model Railroader which also shows the Parallel mounting. I would like to verify if this is the correct application."
Channeling Richard Hendrickson, if you can't see it behind the side sill when the model is on the tracks, does it really matter? I used this area to stash weight on the E&B Valley/Eastern Car Works version of this prototype.