A new line called the T would run all the way down to Hanover Square in the financial district.

Complaints about the inadequacies of New York’s subway system are nothing new. Back in the 1920s, as the benefits of subterranean transport became clear (early worries that riders would choke on underground air had been quickly dispelled), city residents began clamoring for more service to more parts of the city and additional lines to take pressure off the packed trains passing through downtown and midtown Manhattan.

But the city’s privately owned subway operators, the Interborough Rapid Transit Co. (IRT) and the Brooklyn Manhattan Transit Co. (BMT), were slow to the task. Focused on securing a monopoly on underground commuters, they’d laid the first lines with alacrity. (They had the added incentive of exploiting the new transit lines to speculate on newly accessible land in the outer boroughs, a fact that helps to explain why the then-undeveloped north Bronx got a subway in 1917 but the jam-packed East Village is still waiting in 2015.) But building tunnels and laying track was expensive, and after initial expansion the private companies were happier just to rake in fares, especially under the sweetheart contracts the city had provided, which allowed them to extract profits before repaying the city’s costs.

And so City Hall decided to take matters into its own hands. Mayor John Hylan, an avowed foe of the private subway lines, drew up what would become the IND (for Independent) system: a city-owned and -operated subway, with lines running up Sixth and Eighth avenues in Manhattan and out into the boroughs along the Grand Concourse (today’s B and D), Queens Boulevard (the E and F), Fulton Street (A and C), and Smith Street (F), as well as the city’s first cross-town line connecting Brooklyn and Queens (the G).

Once ground was broken on those, the city announced what would be an even more ambitious plan: the Second System, a network of eighteen new lines and hundreds more miles of track that would have brought subway service to almost every corner of New York. A Second Avenue line was to replace the Third Avenue elevated in Manhattan, the future F train would continue east from Second Avenue under the East River to Williamsburg and ultimately via Utica Avenue all the way to Sheepshead Bay, and new lines would venture out along such now-obscure roadways as Lafayette Avenue in the east Bronx and Horace Harding Boulevard (now the Long Island Expressway) in Queens.

Things were looking bright for New York City subway riders. The date was September 15, 1929.

Following the Wall Street crash and the onset of the Great Depression, most of the Second System plans were mothballed, though a few remnants were built, including the beginnings of a massive six-track station that was to be located at South 4th Street in Williamsburg. (The empty station shell still exists, though a more visible artifact survives in the name of the IND’s oddly monikered West 4th Street station, which got “West” appended to avoid confusion with the never-built South 4th.) The Third Avenue el was torn down in 1955, but work on the Second Avenue subway didn’t begin until 1972 — and then ground to a halt three years later, amid the city’s fiscal crisis.

If the first stretch, which will divert a branch of the Q line from 59th Street to 96th Street, opens next December as planned, it will be precisely 87 years and three months after it was proposed. (The MTA hasn’t set a target date for the second phase, which would extend the line to 125th Street, and the agency’s current capital budget doesn’t even include plans for the final stage, a new line called the T, which would run all the way down to Hanover Square in the financial district.)

Otherwise, the last great planned expansion of the New York City subway system exists mostly as a series of ghosts: odd patterns in the ceilings of the Second Avenue and East Broadway F stations, and an abandoned platform that now serves as the mezzanine of the Utica Avenue A/C station. There’s also that station shell at South 4th Street, perched above the Broadway G stop, which was in the news a few years back for hosting a guerrilla art installation that resulted in twenty arrests and the city fencing off the once-hidden station entrance. The artwork, though, was left untouched.