Several subway lines can be taken at the DeKalb Avenue subway station, at the intersection with Flatbush Avenue in Brooklyn. A jocular subway announcement was printed in the Daily News (New York, NY) on July 25, 1982:
   
“DeKalb Avenue, change here for the ‘B’ as in boy, the ‘D’ as in dog, the ‘N’ and the ‘RR’  as in Nancy and Ronald Reagan.”
 
The “RR” became simply the “R” in 1985. The RR subway line was also called the “Rosh Hashanna Rocket” because of its many Jewish riders. The N/R subway lines are sometimes called “Never/Rarely.”
   
       
Wikipedia: DeKalb Avenue (BMT lines)
DeKalb Avenue is a local station shared by the BMT Fourth Avenue Line and the BMT Brighton Line of the New York City Subway, located at the intersection of DeKalb and Flatbush Avenues in Brooklyn. It is served by the Q and R train at all times, the B train on weekdays, and the D and N trains during late nights. During rush hours only, a few W train trips in the peak direction also serve this station.
 
25 July 1982, Daily News (New York, NY), “Only in New York,” Sunday News Magazine sec., pg. 4, col. 3:
But not for the GG, as in Good Government
Heard on the loudspeaker at the Dekalb Avenue subway station: “Dekalb Avenue, change here for the ‘B’ as in boy, the ‘D’ as in dog, the ‘N’ and the ‘RR’  as in Nancy and Ronald Reagan.”
—Larry Fendrick
(An illustration of Nancy and Ronald Reagan in a subway car is shown.—ed.)
     
26 December 1982, Asbury Park (NJ) Press, “Subway systems around the world help speed tourists” by Steve Birnbaum, pg. H1, col. 5:
And then there are the comedians. such as the conductor who announces “De Kalb Avenue Station. Change here for the ‘B’ as in boy, the ‘D’ as in dog, the ‘N’ and the ‘RR’ as in Nancy and Ronald Reagan.” New York’s got a million of ‘em.
   
SubChat.com
Re: Nicknames Of The Subway Lines
Posted by monorail on Thu May 17 23:30:31 2007, in response to Nicknames Of The Subway Lines, posted by E Line Fan on Thu May 17 14:45:38 2007.
 
A—Alligator
B—Boy
CC-Crocodile
D—Dog
LL-Lousy Louie; Losers of Life
M—Mary; Metro-Myrtle-Mugger-Mover
N—Nancy
RR-Rock & Roll
 
SubChat.com
Re: Nicknames Of The Subway Lines
Posted by Larry Fendrick (NotchIt)-Webmaster on Thu May 17 16:30:14 2007, in response to Nicknames Of The Subway Lines, posted by E Line Fan on Thu May 17 14:45:38 2007.
From the Daily News in the early 80’s:
(The 1982 Daily News piece is shown.—ed.)
 
Posted by BrooklynBus on Fri May 18 11:21:01 2007, in response to Re: Nicknames Of The Subway Lines, posted by Larry Fendrick (NotchIt)-Webmaster on Thu May 17 16:30:14 2007.
I actually remember hearing that very announcement. It was my all time favorite. I thought of sending it in but never did. I’m glad you did. It was too good not to immortalize.