NEW YORK CITY SUBWAY CHAINING

In order to identify locations on the subway system, the TA uses a series of letters and numbers on each signal. Each signal has a number plate which identifies the distance from a zero point. A typical BMT or IND sign looks like:

Line A - Track 213,500 feet from zero

On the BMT and IND the even tracks are NORTHBOUND and the odd tracks are SOUTHBOUND. Track 1 and 2 are local and tracks 3 and 4 are express. On three track lines (D line in Brooklyn) the signals for the middle track northbound direction are track 4 and the southbound signals are track 3.

IRT CHAINING CODES

IND CHAINING CODES

Some additional information from Jeff Erlitz and Shalom Septimus, friends of the JoeKorNer

BMT CHAINING CODES

Key to zero locations:

NOTE about BMT line A and the Manhattan Bridge. In November 1967 the IND and BMT lines were merged via the Chrystie St. Connection. Prior to the merger, the two south tracks of the Manhattan Bridge were line H from Chambers St to Myrtle Ave and the two north tracks were line A from 57/7 to CI via Brighton. After the merger, the mid-point of the bridge became the change-over location of the two lines. There the line A tracks form Brooklyn become the Line B tracks of the IND and the H tracks from Brooklyn become the A tracks of the original line to Broadway.
The H designation on 2005 information shows it ending south of Prince St.and the stubs from Chambers St are now J

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IND CHAINING CODES

On the BMT and IND the even tracks are NORTHBOUND and the odd tracks are SOUTHBOUND. Track 1 and 2 are local and tracks 3 and 4 are express. On three track lines (F line in Brooklyn) the signals for the middle track northbound direction are track 4 and the southbound signals are track 3.

IRT CHAINING CODES

BMT CHAINING CODES

The IND zero is a theoretical point in New York Bay at the intersection of the extension of the West 4th St Station and the NY-NJ stateline in the Bay. The distance from the zero is measured from there to West 4th Street. That distance is the chaining point of the station from zero. All other points increase from there north bound and decrease south bound along the line.

The LIRR zero for the Rockaway line is a throwback to the time when the line was part of the LIRR. The zero is in Long Island City via the the Montauk line to where the old Rockaway line diverted from the mailine.

See the BMT CHAINING - K section for the zero of the K line.

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IRT CHAINING CODES

The IRT sign is a little different from the BMT and IND signs. A typical IRT sign looks like:

Line L 14,300 feet from zero Track #2 (This sign had been upsidedown - L on top - since the page was published in 1998. This week ROBERT MARRERO pointed out to me that the L should be on the bottom. His prize is this note on the page.)

On the IRT the signal track numbers are odd NORTHBOUND, even SOUTHBOUND with 1 and 2 being the express tracks. On three track lines, the middle track is 'M'. The track numbers used in stations though are numbered 1,2,3,4 from west to east.

As noted above, each line has a lettered name associated with it. (Do not confuse these letters with the train letters and numbers described in Subway Line Names Page.

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BMT CHAINING CODES

IND CHAINING CODES

Zero locations:

Saturday September 3, 2005
Copyright © 2005 by Joseph D. Korman