The construction of the Second Avenue subway on the Upper East Side has been an epic odyssey, and after decades of false starts, the first phase finally rolled with the start of the new year.

The new subway line officially opened to the public at noon on Jan. 1, 2017.

The journey to launch the line goes back to the 1920s, when the route was first proposed by a state agency. Construction was derailed by the Great Depression, World War II, the city’s financial woes in the 1970s as well as the challenges of building in one of the densest neighborhoods in the country.

The state finally broke ground on the first phase of the line in April 2007, although construction work had been undertaken in previous decades in Chinatown and East Harlem.

MTA officials say the Second Avenue subway will allow residents and commuters easier access to mass transit on the city’s East Side.

The subway line, the first major expansion of the system in more than 50 years, will span 8.5 miles from 125th Street in Harlem to Hanover Square in lower Manhattan.

“There are many benefits. It will give the Upper East Side more travel options that they didn’t have,” said board member Andrew Albert, chairman of the Transit Riders Council.

Here’s what else you need to know about the Second Avenue subway.

Easing ridership pressure on the Lexington line

A major goal for the MTA in creating

A major goal for the MTA in creating the Second Avenue subway was to ease ridership pressure on the Lexington Avenue route, which previously carried 1.3 million riders daily.

After opening with limited service on New Year's Day, the Second Avenue subway averaged 155,000 daily riders by Jan. 27. At the same time, the MTA has seen an 87,170 drop in daily ridership on the Lexington Avenue line at the four stations that run parallel to Second Avenue's service, when compared to the same time period last year.

The MTA anticipated the first phase of the new subway route would be used by 200,000 people each weekday.

Currently, the Lexington Avenue route is served by the No. 4, 5 and 6 trains. That's in stark contrast to the Upper West Side, which is served by both the Broadway lines (No. 1, 2 and 3 trains) and the Central Park West lines (the B and C trains).

The Upper East Side once had two other subway routes on Second and Third avenues, but the noisy elevated tracks were torn down to improve real estate values.

(Credit: Getty Images / Michael Nagle)

First phase opened Jan. 1

The Second Avenue subway was designed to be

The Second Avenue subway was designed to be built in four phases. The $4.5 billion first phase includes stations on 96th, 86th and 72nd streets, as well as an expansion to the 63rd Street-Lexington Avenue station. It opened to the public on Jan. 1, 2017.

MTA officials had been hesitant to commit to a launch date, but with a little push from Gov. Andrew M. Cuomo, the line's inaugural ride took off on New Year's Eve during a private event with city officials.

"There were two things that I never expected would happen. One was the Cubs winning the World Series. The second was having a gala New Year's Eve celebration for the opening of the Second Avenue line," MTA chairman Thomas Prendergast said.

Commuters were able to take their first ride under Second Avenue the next day.

(Credit: Getty Images / Yana Paskova)

Completion dates for Second Avenue subway phases 2-4: unknown

It's unclear when the other three phases will
It's unclear when the other three phases will be completed or how much they will cost. There is over $1 billion budgeted in the 2015-2019 capital plan for design work and utility location for the second phase that runs to East Harlem, with tunneling expected to begin after 2019. The third phase will run to Houston Street and the fourth to the Financial District. (Credit: MTA / Rehema Trimiew)



Stations will be cooler and more accessible

While there may not be air conditioning at
While there may not be air conditioning at the new stations, it will feel about 10 degrees cooler than it is on the street due to climate controls. The current and future stations will all have Wi-Fi and porcelain panels that are easier to clean. They will also be accessible by wheelchair; there will be elevators and escalators. The stations are being constructed without columns to give them a feeling of openness. (Credit: Getty Images / Yana Paskova)

Artwork at the new stations

Much like the Fulton Center and 34th Street-Hudson

Much like the Fulton Center and 34th Street-Hudson Yards station, the new Second Avenue subway stations boast some intriguing public art installations. The MTA enlisted four artists for the job and gave each of them their own station as a blank canvas.

At the expanded 63rd Street station, Jean Shin brings history to life in "Elevated." The artwork spans four floors and incorporates archival photos, pictured, from the old elevated tracks that ran along Second and Third avenues.

Vik Muniz's "Perfect Strangers" installation at the 72nd Street station takes on a more eclectic feel, featuring over three dozen colorful characters representing New Yorkers from all walks of life.

It's pretty hard to miss the nearly 9-foot-tall portraits as you walk through the station entrances and mezzanine concourses at the 86th Street station. Chuck Close took 10 of his highly-detailed, photo-based portrait paintings and turned them into mosaic and ceramic tile to create "Subway Portraits." The people portrayed are real-life cultural figures, including Lou Reed.

"Blueprint for a Landscape" spans nearly 14,000 square feet throughout the 96th Street station. Sarah Sze's design includes objects like sheets of paper, birds and trees within a blueprint-like design that references energy fields and wind patterns.

(Credit: Office of Gov. Andrew M. Cuomo / Tara Foster)

The Q train serves the Second Avenue subway

With the opening of the first phase, Q
With the opening of the first phase, Q trains now run along Second Avenue. To supplement service to Queens, the MTA brought back the W train, which was suspended in 2010. The W, reintroduced in November 2016, now runs local between Whitehall Street in Manhattan and Astoria-Ditmars Boulevard in Queens. (Credit: Charles Eckert)

The project's cost was once estimated at $86M

When the Second Avenue subway was proposed in
When the Second Avenue subway was proposed in the 1920s, it was estimated it would cost $86 million to build it from the Harlem River to Houston Street. The MTA is actually spending $4.5 billion on just the first phase alone, which includes three new stops, as well as the connection to the Lexington Avenue-63rd Street station. (Credit: Getty Images / Yana Paskova)