Number, Letter, Color Code Systems

BMT Number Code
IRT Number Code
IND/BMT Letter Code
Color Code

Most people now refer to trains and even the lines the trains run on by the letters and numbers displayed prominently on the trains, on station signs, and on the official subway map. Years ago, it was more common to refer to subway lines by division-- IRT, BMT, IND-- and named route-- Lexington, Sea Beach, and so on. Use of letter codes first became popular with the IND lines that opened starting in 1932. Management began emphasizing the letters and numbers in 1967, when the BMT and IND divisions merged and caused establishment of several new routings. Many New Yorkers still use the older names in addition to the letters and numbers.

BMT Number Code

The first New York subway route code was the now-forgotten BMT code of about 1925. It was always in rather limited use, because most of the trains the BMT had never could display it-- not the steel "standards" of the subway, nor any of the elevated trains. It was not normally seen on maps or station signs either. New cars placed in service from 1927 to 1955 did show the numbers. Officially, the extended IND letter code replaced the numbers in 1960, but some trains displayed the numbers as late as 1967, as noted below.

In the number code, trains on the Broadway mainline were classified according to their Brooklyn route. Passengers also needed to notice whether the train was express or local, and whether it crossed "via bridge" or "via tunnel". Trains to Coney Island had to be distinguished by the number or by a route sign. Passengers for Queens needed to check the destination sign.

Trains on the elevated and other lines were designated simply by route and terminal for the most part.

Notes:

*Continues a route previously unmarked.

Dates in () parentheses indicate routes rarely marked, because normally assigned cars did not display markers.

Lines with no dates were never marked, but are included to show the complete numbering scheme.

Marker 17 was reported someplace for 14th St--Fulton (Fulton east of East New York) but I've been told the train actually ran with 13 markers, as listed here.

IRT Number Code

The number code now in use for the former IRT lines was developed later than the letter code and was first seen on cars put in service in 1948. As a result the IRT elevated division never used the code (except for a late remnant of the Third Ave Elevated).

IRT trains had been classified by signs showing the main line, express or local, and destination, thus "7th Ave Express to 145th St". The north and south terminals of express trains were never closely correlated, but this did not matter as long as no route numbers were used. Generally, Lexington expresses ran express in Brooklyn to Atlantic or Utica Avenues, and 7th Ave expresses ran local in Brooklyn to the ends of the branches, but the routing in Brooklyn was quite flexible and some variant runs remain to this day.

When the number code came in, it designated main line and northern terminal. The same problem of favoring one side therefore exists, and riders in Brooklyn have seen changes in number codes that do not indicate any change in service, such as from 2 to 3 for the 7th Ave train from New Lots Ave to Manhattan.

The original code of 1948 is similar to what is now used, except for 8 and 9. A green 10 sign has been spotted on recent cars, but I don't know yet what it would designate. Nothing equivalent to the double letters for local was implemented, so some numbers designated both a local and express service.

Notes:

*Contination of a route previously unmarked. The designation "Brooklyn" here indicates trains went to various terminals.

IND/BMT Letter Code

The letter code used today for about two-thirds of the system dates from the opening of the Independent Subway and must have been planned from about 1930. The original code ran from A to H only.

The format of single letters for express, double for local, was used from the beginning until 1985. There were always some anomalies, notably the "express" E and F that were locals in Manhattan.

There is a bad flaw in this plan that has never been resolved. Most train routes run from an outer terminal through Manhattan to another outer terminal, but the letter designates a combination of the main line and only one of the outer terminals. For example, D indicates 6th Ave main line and Concourse branch, and thus the Concourse line has been consistently served by a D train since 1940. The IND plan may be said to favor the northern terminals: A B always Washington Heights, C D always Concourse, and E F always Queens. The southern terminals, by contrast, change markers in accordance with where the train's northern terminal is, something of little interest to most riders. Thus the Smith Street (Culver) line changed from D to F in 1967, signifying no difference at all in the service from Brooklyn to Manhattan. On the other hand, the letters used later for former BMT routes followed BMT practice of favoring the southern terminal for those lines. This has led to a close identification of one old IND letter, B, with the BMT West End route, shifting its meaning so that for most of the week it no longer designates Washington Heights as it once did.

Following is the original IND code used up to 1967, showing all the markers actually used. IND trains carried rollsigns for all possible single and double letters and some even differentiated "6th Ave" and "6th Ave--Houston".

The code was extended in 1960 to BMT routes using letters from J to T, and until 1967, it co-existed with trains showing the BMT number code and trains showing neither number nor letter. One deviant pair of markers, QB and QT, was used instead of QQ to differentiate the two different Brighton local services via bridge and tunnel. Several other mixed-letter codes were used until 1973 to try to indicate pairings of north and south terminals, such as QJ for a train running to the Brighton Beach Q and Jamaica J branches, but this attempt at solving a problem was not applied consistently or well. The QJ for example ended up in use for a trainroute that never ran to the Brighton Beach line.

The new trainroutes starting in 1967 included several that were hard to characterize as express or local, being express in one place and local in another. For this reason, and to simplify clutter, all trains were designated with single letters beginning in 1985. The only letter change this forced was AA, first to K and then to C.

Notes:

*Continuation of a route previously unmarked, or marked using the BMT number code.

Color Code

Up to 1967, the subway map and signage had used the three old system names, IRT, BMT and IND, as the first-order division of the subway system.

With the merging of the BMT and IND routes in 1967, the three old system names were officially dropped, although they were still commonly used on existing signs and ordinary speech. Instead of divisions, only the route letters and numbers were used, and a multi-colored "spaghetti" map was put into use that proved difficult to comprehend because of the detail. (See 1974 version of map here). A table of the route colors from the New York City Transit Authority Graphics Standards Manual, 1970 edition, follows, including the Pantone color matching system values.

In 1979, the current color code was introduced, grouping trains by main line. A new map was introduced, and new signage was rapidly installed using the colors as background for the number and letter circles on signs. The color code greatly simplified the map and groups the trains into logical families.

Unfortunately, the color code has yet to be used to full advantage. Lines are not referred to by color, as "the red line", nor by names corresponding to colors, as "the Seventh Ave line". Instead, signage and official announcements continue to identify lines by fussy details of train letters and numbers.

For example, an express station on the 7th Ave subway "red line" downtown is marked at the entrance with numbers 1, 2, 3 and 9 each in a red circle and would be referred to in announcements as the "1-2-3-9 line". This usage requires changes in maps and station signs for service changes entirely within one "line". For example, when the Brooklyn terminals of the 2 and 3 were swapped, if maps and station signs had used "Seventh Ave Line", no change would have been required, since all stations with "red line" service continued to have it.