2. Lines and routes

New York City Subway nomenclature and List of New York City Subway lines

Many rapid transit systems run relatively static routings, so that a train "line" is more or less synonymous with a train "route". In New York, routings change often as new connections are opened or service patterns change. The "line" describes the physical railroad line or series of lines that a train "route" uses on its way from one terminal to another.

"Routes" (also called "services") are distinguished by a letter or a number. "Lines" have names.

There are 26 train services in the subway system, including three short shuttles. Each route has a color, representing the Manhattan trunk line of the particular service; a different color is assigned to the Crosstown Line (G) route, since it does not operate in Manhattan, and shuttles are all colored dark gray. Each service is also named after its Manhattan (or crosstown) trunk line, and is labeled as local or express.

The current color system depicted on official subway maps was proposed by R. Raleigh D'Adamo, a lawyer who entered a contest sponsored by the Transit Authority in 1964. D'Adamo proposed replacing a map that used only three colors (representing the three operating entities of the subway network) with a map that used a different color for each line. D'Adamo's contest entry shared first place with two others and led the Transit Authority to adopt a multi-colored scheme. (D'Adamo subsequently earned a master's degree in transportation planning and engineering from Polytechnic University and worked for transit authorities, including a stint at the MTA, and was responsible for organizing and building what today is the Westchester County Bee-Line bus system.) However, the lines are not referred to by color (e.g., Blue line or Green line), although the colors are often assigned through their groups (A, C, and E are blue whereas the 4, 5, and 6 are green).