A physical network diagram database for the New York City subway system, covering Division A (IRT), Division B1 (BMT), and Division B2 (IND). Station data is organised by line chain and build route, with engineer's chain distances, build era, CBTC status, and station setup type.

Data compiled from NYCT Signal and Engineering prints, NYCTA Engineering Guidelines Volumes 1 and 2, NYCT route and section documents, and NYCT Draw. Build and construction data are also pulled from RTC, PSC, BOT, TA, and MTA records, documents, and annual reviews. Chain distances based on the engineer's chain notation (1+00 = 100 ft), measured from the north end of each station.

The Subways.io Diagram Database documents the NYC subway as physical infrastructure — every station, every line chain, every construction route across the three operating divisions: A (IRT), B1 (BMT), and B2 (IND). Navigate using the four views in the top bar, or via the bottom navigation on mobile.

Line Key  — the default landing view. The complete list of all 45 line chains across the three divisions, with chain zero (the datum point), direction, and station count. Tap any chain to drill into its station list.

Chain  — the station list for the current chain. Each station shows its marker (engineer's chain notation, e.g. 624+50), opening year, setup type code, and era. Tap a station to open its full detail card. Use the chain pills (top of view on desktop, dedicated row on mobile) to switch between chains in the current division.

Route  — opens the Route Key, a system-wide table of all 66 construction routes — IRT contracts, numbered routes, capital projects, and BRT-era private routes. Each row shows the route's corridor name, line chains, divisions, contract code, and assigned services (the colored bullets). Filter by division at the top. Tap any route to view its station list, organized by build section. Dimmed routes indicate no station data is mapped yet.

Crossings  — water crossings system-wide. East River, Harlem River, Newtown Creek, Beach Channel, Flushing River, and others. Each entry shows the structure type, approach grade, division, and year opened.

Tap the Search button in the top bar (or press ⌘K / Ctrl+K) to open the global search modal. Type any part of a station name or route — results show inline with division and chain badges, with the matched text highlighted. Use the arrow keys to navigate, Enter to open the selected result.

Tap any station in a chain or route list to open its full detail card. The card is organized into sections:

Location — Division and borough.

Chain & Distance — Chain zero (the datum point for measurements), the station's marker at the north end (engineer's chain notation: 1+00 = 100 ft from chain zero), and the computed distance from chain zero in feet and miles.

Station — Opening year, build era (color-coded pill), route designations, route section, ADA accessibility status, terminal type (Reverse, Stub-End, Relay, etc.), and notable engineering characteristics (depth, height, Bi-Level designation).

Technical — Tracks count, MOW Type, station setup (Elevated, Underground, etc.), setup type code (E1–E4, U1–U6, G1–G4, X1–X3), platform configuration, platform code (P1–P6), thoroughfare width at street level, CBTC status, ATS-A status (A-division only), and a Platform Lengths sub-section showing original and extension lengths over time.

Former Service / Formerly — Historical service designations (ex-LIRR, elevated lines, etc.) and former station names with era or year context.

Notes — Supplementary engineering or operational notes.

In Chain mode, two filter pills appear below the route pills: Era and Setup. Tap a pill to open a dropdown of values present in the current chain, each with a station count. Selections are multi-select within a pill (OR logic) and AND-combined across pills — e.g., (era = BOT OR Dual Contracts) AND (setup = U1 OR U2). Active filters get an amber outline on the pill. Clear all filters with the Clear ✕ button.

The Division pills (A — IRT, B1 — BMT, B2 — IND, All) at the top scope the visible chains. In ALL mode, chains from every division are shown together.

Some routes were built across two divisions (e.g., Route 5 — Broadway & Lexington spans A and B1). In the route detail view for these routes, the static division tag is replaced with switchable division pills. Tap a pill to view that division's segment of the route. The current division is filled with the division's color (red A, blue B1, green B2).

CBTC dot — In every station list and on the station card, the CBTC dot indicates Communications-Based Train Control status:

   Active (e.g., L line, 7 line)

   In progress

   Not active

ATS-A row (A-division only) — Automatic Train Supervision for the IRT. All A-division stations on chains other than C and CC are under Siemens ATS-A supervision. The B-division skipped ATS-B and went directly to CBTC, so B-division station cards don't show an ATS row.

The colored circles in the Route Key represent train services using the MTA's standard color palette:

1 2 3  Red — Broadway / 7th Ave local & express   4 5 6  Green — Lexington Ave   7  Purple — Flushing   A C E  Blue — 8th Ave   B D F M  Orange — 6th Ave   G  Light green — Crosstown   J Z  Brown — Nassau Street   L S H  Gray — Canarsie & shuttles   N Q R W  Yellow — Broadway BMT

For full term definitions, open the Glossary from the top bar. Quick reference:

Setup types — E1 standard steel elevated · E2 high elevated / viaduct · E3 concrete elevated · E4 dual-level elevated · U1 shallow cut-and-cover · U2 deep cut-and-cover · U3 mined / rock station · U4 bored / tube station · U5 deep bore · U6 dual-level underground · G1 at grade · G2 embankment · G3 open cut · G4 retained cut / trench · X1 mixed / composite · X2 major rebuilt or altered type · X3 underground truss / bridge setup

Platform codes — P1 two side platforms · P2 one island platform · P3 one side platform · P4 bi-level side platforms · P5 bi-level island · P6 loop / terminal

Build eras (color-coded pills) — Early IRT · Dual Contracts · Triboro · BOT (Board of Transportation) · Converted Rail (formerly LIRR / NY Westchester & Boston / etc.) · TA · MTA · MTA Capital

Contract codes (in Route Key) — C1, C2, C3, C4: IRT Contracts · TB: Triboro · IND: Independent Subway System · BRT: Brooklyn Rapid Transit (private builder) · C209 and similar: modern MTA capital contracts

ADA badge (green) — Station is ADA accessible.

Closed stations — Dimmed in lists (e.g., City Hall Loop, Worth Street, 18th Street).

Dot (•) next to a station name — Station has additional notes available.

Era pill — Colored badge indicating the build era of the station.

Home button — Returns to Line Key from anywhere in the app.

Search — ⌘K / Ctrl+K opens global search.

Tab bar — In Chain mode, switch between Stations and Infrastructure tabs. The Infrastructure tab shows track grades for the current chain (3.5%+ grades flagged by severity tier).

Route Key back link — In a route detail view, tap "← Route Key" at the top of the header to return to the overview.

Mobile — Use the bottom navigation bar to switch between Key, Chain, Route, Crossings, and More (overflow menu for Guide, Glossary, About, and Download Diagram).

Glossary — 62 terms across 11 sections, accessible from the top bar.