I wish that my good friend Dave Garcia was still with us. He might have been able to talk about the brake schedule that you encountered on the caboose.
I recall one-time, years ago, when Dave and I looked over the former F&CC/Uintah/E-N locomotive that is now at the Southern Nevada State RR Museum. As we talked around it and looked under the tender, Dave remarked that the tender still had the triple valve that allowed for changing between straight and auto air braking! He was both surprised and enthused by this discovery.
Brian Norden
PS Dave passed on early during the pandemic.from a heart attack while hospitalized for Covid-19.