NXSYS, Signalling and Interlocking Simulator

New February 2022: New versions of the application(s) have been released, including up-to-date 64-bit and 32-bit Windows executables as a standard MSI installer, including all features from the last 5 years, and a new documentation/help system including a new document on signalling logic design and a greatly updated main help document. See the downloads section below.

Here are the current Windows and macOS downloadables for NXSYS (enn-ex-sys), my simulator of relay logic signalling and interlocking as (still) used in New York City, but rapidly being replaced by more recent technologies (viz., CBTC, “Communications-based train control”).

Relay-based fixed-block wayside color-light signalling, as this breed is known, is a product of the technological world of a century ago, of Titanic, before radio, television, and the semiconductor digital computer (but I believe that these complex logic engines are fairly called “early computers”). Parts of New York City’s system are, in fact, almost that old, and inability to maintain it (in particular, obtain replacement parts) has made this venerable collection of clattering junk the whipping boy for all of the city’s current transportation shortfalls.

Nevertheless, when I, half that time ago as a boy in New York, met this system through the then-front windows of trains, it meshed with my nascent interest in “electricity” in a way that thrilled me, and when a generous TA employee, in response to my typewritten letters, showed me the new control panel at DeKalb Avenue (in 1962? 3?), my curiosity about and affection for its technology was born, and has not really ever ceased. In 1966, I was profoundly fortunate to then receive, in a now unimaginable pre-9/11 world, a requested 50-page copy of NX & UR INTERLOCKINGS TYPICAL CIRCUITS DWG. 733-33, which I began to treasure as much as the St. Matthew Passion.

While I then spent countless hours designing interlockings according to these specifications (including round-the-clock for all of August 1966), all of my designs were as computer programs written in a (paper) notebook, worthless without being able to “run” them. Thirty years later I finally had enough computer power (and skill) to implement a system that could “run” such designs in simulation. That’s NXSYS, which has put me in contact, as relays say, with signal engineers, transit employees, and railfans appreciative of and able to help me improve my work. A full telling of my involvement, such as it was, with the New York Subways is available here.

I have already written an extensive tutorial sub-site on “classic New York City Subway signalling” aka “that antique century-old dysfunctional dinosaur keeping New York City in the Stone Age”, including an explanation of interlocking, and a brief description of NXSYS (formerly downloadable there). (nycsubway.org is a terrific site run by David Pirmann, which is not affiliated with New York City Transit or any other transportation provider.)

For that matter, neither am I affiliated with any transportation provider or engineering firm, although I have friends who are or were.

Forrás: https://bernardgreenberg.com/Subway/