I remember the brake handle on the R-1/9s, along with all of their associated sounds: moans, groans, grunts, snarls, hisses, throbbing compressors, AMUE lap-release sounds, door sounds, and the unmistakeable whine of their bull and pinion gears.
The NX is an honorable mention; although I never had a chance to ride on it, I do remember seeing it on maps. In fact, I still have a 1967 TA map - the first one with a color for each individual route.
I remember seeing wooden platforms at Marcy Ave.
I can add a few: taking a JJ and, later, QJ to the end of the Jamaica line at 168th St.
Crossing the Williamsburg Bridge on a #15.
Rocketing along CPW on an A train of R-10s.
D trains to Coney Island via the Culver line.
Shiny new R-32s in 1965.
Using the lower level at 42nd St. as an underpass between the platforms.