When I was a small boy, five years old in 1950, we used to take the Brewster local on the Harlem division, from either 125th St. or Grand Central (we lived in upper Manhattan), to visit my uncles (mom's brothers) who lived in Thornwood and Pleasantville. A couple things still stand out in my memory of those trips.
One, is that the electric motor, sometimes a big one when the train was long, from Grand Central was swapped out in North White Plains for a pretty thrashed looking Pacific. I knew this to be true because I kept hoping to see a Hudson, like in the Lionel showroom, but alas, it usually was a grimed up 4-6-2. Dad, knowing I was train crazy, used to take me off the train to observe the engine swap. In later years the loco changed to an Alco RS and I lost interest.
The other is that, when we left from Grand Central the train annunciator would say over the crappy pa echoing through the terminal something like . . . "Now leaving from track 97, the Brewster local. Making station stops at . . . " completely unintelligble for about half a minute followed by " . . . and Brewster!"
Pete