Welcome to Curbed’s first-ever Transportation Week! From how to improve public transportation in cities, ranking the best car-free neighborhoods across the country, and a friendly competition between NYC, San Francisco, and Los Angeles to determine which has the best public transit, this week is all about how we get around in our favorite cities. All aboard!

The New York City subway system is a marvel to take in, flaws and all, filled with a rich and vibrant history. One of its most intriguing components of its past is the evolution of its subway cars.

To understand why and how subway cars have changed over time, it helps to know the basic history of how the city’s unified transit system came to be. Before there was the Metropolitan Transportation Authority (MTA), there were three subway lines that ran independent of each other: Interborough Rapid Transit (IRT), Brooklyn-Manhattan Transit (BMT), and Independent Rapid Transit Railroad (IND), all of which will make appearances in this abridged history of subway cars.

Those three systems were combined in 1953 into one city-run conglomerate: the New York City Transit Authority, which was later absorbed by the state into the newly-created MTA in 1968. By that point, the cars used to transport people around the city had evolved from steam-powered above-ground trains to hulking (and soon-to-be graffiti-covered) subway cars. And more innovation was yet to come—read on to see how the evolution happened.

19th century: When “els” ran the city

Elevated trains, simply known as “els,” first debuted in the late 19th century, giving New Yorkers an alternative to traversing the city by way of horse and carriage or street-level trolley. The first dedicated line ran along Greenwich Street and Ninth Avenue, according to the MTA. Its steam-powered cars were constructed from wood and were modeled on the western train cars of the time.

While the idea of underground subways had been floated for some time—Alfred Ely Beach constructed New York’s first mode of underground transport in 1870, though it only lasted for three years—it wasn’t until the Great Blizzard of 1888 that the importance of an underground subway system became really apparent.

1904: The earliest subway cars

The IRT got to underground transit first: On October 27, 1904, the company opened the first underground subway line, stretching from the glorious old City Hall station in lower Manhattan to 145th Street in Harlem. The BMT (or BRT as it was known before going bankrupt) followed suit soon after, but made the odd choice to operate wooden cars that had previously been used as elevated trains in its newly-formed underground system. That came to an end in 1918, after one of those wooden cars crashed in a subway tunnel near Prospect Park, killing 93 passengers.

The IRT’s “Composite” cars, as they were called, featured wooden bodies sheathed in copper and coaches with fabric seats that were secured to a steel underframe. The cars were spacious, but there were only two set of doors on either side of the cars where passengers could board and exit the train. The conductor had to manually open and close gates in each station for on and off-boarding (imagine dealing with that in today’s rush-hour commute). The cars were modified in 1910 to include a center door but otherwise remained the same until they were replaced by all-steel cars.

The IRT rolled out “Pullman” style cars, constructed from stainless steel, in 1915 and there were at least eight style variations introduced between then and 1938. The seats were still covered in fabric, but the cars overall offered more standing room.

Meanwhile in 1915, BMT presented the “Standard,” a subway car with steel bodies that were wider and longer than IRT cars. Standards also had more standing room, brighter lights, and bigger windows than the IRT’s stainless steel subway cars.

1932: The IND debuts its own cars

In an effort to compete with the two private lines, the city opened its own subway line, the IND, in 1932. IND cars were similar to BMT cars in design, but were bigger than IRT line cars in length and width, requiring tunnels that varied in size. If you’ve ever wondered why today’s cars come in so many different capacities—letter trains are typically wider than number trains—it’s because despite the system still uses the original tunnels from the IRT and BMT. Smaller trains can pass through wider tunnels, but it doesn’t work the other way around.

The IND’s R-type cars—or “City Cars”—“combined the best features of IRT cars (speed) with the best of the BMT (large passenger capacity),” according to the New York Transit Museum. They were initially painted a dull green—fitting, considering they were rolled out during the Great Depression—and were the first cars to introduce four doors on each side, speeding up the loading and unloading process at each station.

1950s: The first air conditioned subway cars

Fast forward to the 1950s: By that point, the city had purchased the BMT and IRT private lines, unifying the three disparate systems into the New York City Transit Authority. A number of different R-type cars had been introduced over the years, each with slight variations to the previous version. But the most significant—and crucial, in an ever-more populated subway system—change was the introduction of air conditioning.

The R-15 car, introduced in 1950, was the first attempt at bringing air conditioning into subway cars. But it wasn’t without its flaws, many of which will seem familiar to passengers on today’s trains. As the Transit Museum describes it, “the cars were often damp and water dripped on passengers.” (Ew.)

Eventually air conditioning was removed and replaced with conventional fans since it was too costly to keep up with the many repairs they required on a regular basis. In 1966, the R-38 was the first fleet of subway cars to offer air conditioning that actually worked.

1970s: The decline of the subway

By the 1970s, it seemed as if the city’s subway system was at an innovation standstill. New subway cars weren’t being put forth as often and thanks to a pattern of deferred investment in the subway (thanks, Robert Moses!), maintenance on existing cars began to fall behind.

The R-44 (which currently run on the Staten Island Railway) and R-46 cars were introduced during this period and fitted with plastic seats, but many of the cars were faulty and required constant repairs.

This is also the era in which subway cars served as a canvas for graffiti artists—important for New York’s cultural history, but not exactly beloved by the transit authority.

By the 1980s, more reliable cars were introduced in the form of the R-62 and R-68, or today’s 3, B, D, and G trains (and some older 1, 7, and shuttle trains). Graffiti was still rampant and almost every car in the subway system was tagged, forcing the New York City Transit Authority (NYCTA) to launch a five-year initiative in 1984 to eradicate all graffitied trains.

On May 12, 1989, the city announced that all graffiti had been wiped away from the system’s fleet. To this day, trains are not allowed to leave their yards if there is any graffiti on its exterior.

2000s: The subway cars of today

Which brings us to the 21st century: A new class of subway cars, including the R-142 (which services the 2 train) and the R-143 (the L train) were commissioned in 2000 and 2002, respectively. The new models featured technology that included an electronic strip map and an improved public address system.

The R-160 class was introduced in 2005, with technological advances like LED displays of upcoming stops and FIND (Flexible Information and Notice Display) systems that show time and route information. There are two variations for this model and the cars primarily serve the system’s C, E, F, M, N, Q, W, and Z lines.

The R-188 fleet line, which is similar to R-142 type cars, is one of the newest designs. It was introduced in 2013 and solely services the 7 line.

The future: Open gangway cars, Wi-Fi, and more

Despite these upgrades, modern-day subway cars can still seem outdated when compared to innovations in other countries—and many of the older trains, including the decades-old R32s on the C line, are relics from another era. (This doesn’t even touch on larger problems within the subway system, like its aging signals, but that’s a whole other story.)

But new cars are in the pipeline; last summer, Governor Andrew Cuomo revealed an updated design for over 1,000 new subway cars. The new fleet will feature major upgrades that include a new exterior that boasts LED headlights and interiors with Wi-Fi, USB ports, full-color digital displays, security cameras, door opening alerts, and an open gangway design. These new R-211 cars are expected to roll out in 2023.