Naming of Penn Station Interlockings

In the past, all of the LIRR interlockings we have seen have had some sort of reasoning behind their names. Some are simple and some require a bit of knowledge of your LIRR history. BABYLON interlocking is near Babylon Station, BRENT is near Brentwood, PD stands for Patchogue Dock, FOX is named after retired LIRR conductor Walter J. Fox.

The Penn Station Interlockings, however, seem to have somewhat of a different naming scheme. While A, C, F, KN, JO, Q, R, etc. all seem fairly simple, it’s difficult to determine the origins of their names. Is JO someone’s initials like JS interlocking? Not really.

When the Pennsylvania Railroad first constructed Penn Station back in the 1910’s, they also constructed the four interlockings surrounding the stations. When it came time to give names to the interlocking, the PRR didn’t stop for a minute to play around and simply named the interlockings A, B, C, and D.

Back when New York Penn Station was being built, the Pennsylvania Railroad was still using Morse code. It has been held that the Morse code the railroads used was slightly different than what Google refers to as "international Morse code," but it was pretty similar to the following:

A .-
B -...
C -.-.
D -..
E .
F ..-.
Q --.-
R .-.

It was decided that the B and D sounded too similar, so they were not used, and the PRR moved to change the names of B and D interlockings to make things less confusing. At the time, the PRR just used two available telegraph codes, KN and JO, to take the names of B and D. At that point, A, B, C, and D became A, KN, C, and JO.

Out in Queens, they adopted a similar way of lettering the interlockings. The code for the next letter of the alphabet, E, was just one dot. The PRR, thinking the simplicity of that would cause unnecessary confusion as well, decided to skip over E and name the interlocking on the other side of the East River Tunnels in Queens by the next letter in the alphabet, F.

It has been held that Q interlocking in Queens was given the letter Q since it was east of Queens Boulevard. Q's partner interlocking in Sunnyside, was given the next letter of the alphabet, R.

HAROLD interlocking was the exception. HAROLD interlocking gets its name from Harold Avenue, the street which passes over the current interlocking.  Years ago, the names of many streets and avenues in the Sunnyside/Long Island City section on Queens were re-designated to have number street names.  Harold Avenue was renamed to 39th Street, and that street name is visible on maps today.

All of the other interlocks in this area have somewhat recognizable names (GATE for Hell Gate Bridge, BERGEN for Bergen County, EMPIRE for the Empire Connection, etc.)