Thank you. Great stuff and much appreciated.

It seems there would have to be provision to make a corresponding brake pipe reduction (to equalize with the reduced aux reservoir pressure) after an E-application, or the automatic brake valve on the engine left in "running" position would result in continued recharging of the aux reservoirs. Perhaps it was necessary to put the automatic in "lap" when using the E-brake (?), or perhaps the control valves on the cars had provision to prevent recharging when an E-application was made. In that case, it seems that a quick switch from E-brake to automatic (such as in the event of E-brake failure of some sort) would require going extra deep with the automatic to "catch up" with the existing reduction in the aux reservoirs. Essentially like working with a "soft" brake pipe.

I'm pretty sure I have a diagram and book(s) on the HSC equipment around somewhere. Will have to do some digging.

It's pretty obvious why maintenance on the system led to discontinued use.

Regarding "old heads", the guys I knew were fortunately not like that, but I am quite aware of the type.