D&RGW tender air valves

It seems that the D&RGW had a practice of hanging some brake related devices off of the right side of the tenders close to the cab. Pictures indicate that the "stuff" was updated to newer equipment after around 1940 or so. One of the items which seems to be present in either configuration was an air release cock which, I assume, was tied into the tender air reservoir. This looks like it may have been used in conjunction with a double check valve/safety valve combo (?). Earlier photos show the same release cock but with some other type of valve. Can someone tell me what these things are?