Why Are Some Letters Missing From NYC Subways?

Getty Images
Getty Images

If you’ve ridden the New York City subway, you know that the different trains are often designated by letters of the alphabet (or numbers, but we’re not talking about those).

If you’ve ridden the New York City subway a lot, you know that some letters are missing. And it’s not the tail end of the alphabet, either. There’s an A, B and C train and there’s also a Z train. But there's no H train or Y train. There are several other skipped letters, too.

The explanation for the missing letters falls (mostly) into two categories.


H, K, T, V and W are all former trains that have been discontinued. In fact, an in-depth look at the history of the Metropolitan Transportation Authority (MTA) reveals regular recycling of letters as trains go in and out of use. But let’s look at each of the current letters getting snubbed.


Technically, the H train is still in use. It is the internal name for the Rockaway Park shuttle in Queens that connects with the A train to provide service to the western edge of the peninsula. After a few years without any designation on the map, the shuttle became known as the HH train in 1962. Over the next several decades, it was known as the E and then the CC train. In the 1980s, the MTA did away with double letter designation and the shuttle earned its H name. Eventually, however, all shuttles started bearing the grey S designation on maps. Since this would create internal confusion, the MTA continues to call the Rockaway Park shuttle the H train for their own purposes.

H made a public resurgence as the name of a free shuttle that took over service for a suspended portion of the A train in the aftermath of Hurricane Sandy in 2012. The letter was available as the storm had also knocked out service on the Rockaway Park Shuttle. When both the shuttle and the A train came back online by the summer of 2013, H slipped back into hiding.


The K train used to run on the same Eighth Avenue track that currently sports the A, C, E. It was the name given to the former AA train when the use of double letters was discontinued in 1985. The K train was essentially the opposite of the C. Both ran locally between 168th Street and the World Trade Center, but while C train service covered rush hours, the K took on midday, nights, and weekends. The K last ran on December 10, 1988; the next day, C train service was expanded to include all hours.


T (and TT) used to be the name of what is now known as the D train. It was absorbed by the B train in the 1960s, which was replaced by the W train and ultimately the D train in the early 2000s. If you miss the T train, never fear: It is the future name of the Second Avenue Subway, which is expected to open its first phase in December 2016.


Longtime New Yorkers may remember both the introduction and the dissolution of the short-lived V train. It debuted in December 2001 to replace a rerouted F train, traveling between the Lower East Side in Manhattan and Queens. Unfortunately, limited service patterns—the V only ran weekdays from approximately 6:30 a.m. to midnight—and budget cuts doomed the V train. In June 2010, it was merged with the M train and dropped the V designation.


Another short-lived, late-alphabet train, W debuted in 2001 to account for construction on the Manhattan Bridge tracks that disrupted the B train. During nearly nine years in use, its service area changed several times, going all the way to Coney Island to start, then eventually losing the Brooklyn borough altogether. In Manhattan, W traveled along the Broadway line that we now think of as the N, Q, R train, eventually getting absorbed into those lines in 2010 as a result of financial shortcomings.

Potential Confusion

The letters I and O were never used for trains because of their visual similarities to the numbers 0 and 1 and the use of both alphabetical and numerical designations in the New York Subway system.

U and Y were eliminated from consideration because they are homonyms with actual words—namely, “you” and “why.” Apparently, the founders of what is now the MTA did not find the potential for “Who’s on First”-style confusion to be nearly as humorous as Abbott and Costello did.

The Problem with P

That leaves all the letters accounted for except P. There are several stories of almost-P trains. It was the intended name for the final leg of the Culver service (now the F line) into Manhattan that was scrapped in favor of a shuttle (labeled S as all shuttles are) at the last minute. It was also the name given to a specialty train designed to work around the 1992 potential Amtrak strike. Congress intervened at the last moment and no such emergency service was necessary. The P then stood for the incapacitated Penn Station. However, neither of these instances explain why it was never used for any new trains between the creation of the Culver shuttle and the 1992 near-strike. And so it is fun, if not entirely likely, to consider the theory that the P homonym was simply too immature for polite commuter conversation.

What Is the Kitchen Like on the International Space Station?


Clayton C. Anderson:

The International Space Station (ISS) does not really have a "kitchen" as many of us here on Earth might relate to. But, there is an area called the "galley" which serves the purpose of allowing for food preparation and consumption. I believe the term "galley" comes from the military, and it was used specifically in the space shuttle program. I guess it carried over to the ISS.

The Russian segment had the ONLY galley when I flew in 2007. There was a table for three, and the galley consisted of a water system—allowing us to hydrate our food packages (as needed) with warm (tepid) or hot (extremely) water—and a food warmer. The food warmer designed by the Russians was strictly used for their cans of food (about the size of a can of cat food in America). The U.S. developed a second food warmer (shaped like a briefcase) that we could use to heat the more "flexibly packaged" foodstuffs (packets) sent from America.

Later in the ISS lifetime, a second galley area was provided in the U.S. segment. It is positioned in Node 1 (Unity) and a table is also available there for the astronauts' dining pleasures. Apparently, it was added because of the increasing crew size experienced these days (6), to have more options. During my brief visit to ISS in 2010 (12 days or so) as a Discovery crewmember, I found the mealtimes to be much more segregated than when I spent five months on board. The Russians ate in the Russian segment. The shuttle astronauts ate in the shuttle. The U.S. ISS astronauts ate in Node 1, but often at totally different times. While we did have a combined dinner in Node 1 during STS-131 (with the Expedition 23 crew), this is one of the perceived negatives of the "multiple-galley" scenario. My long duration stint on ISS was highlighted by the fact that Fyodor Yurchikhin, Oleg Kotov, and I had every single meal together. The fellowship we—or at least I—experienced during those meals is something I will never, ever forget. We laughed, we argued, we celebrated, we mourned …, all around our zero-gravity "dinner table." Awesome stuff!

This post originally appeared on Quora. Click here to view.

Clayton "Astro Clay" Anderson is an astronaut, motivational speaker, author, and STEAM education advocate.

His award-winning book The Ordinary Spaceman, Astronaut Edition Fisher Space Pen, and new children's books A is for Astronaut; Blasting Through the Alphabet and It's a Question of Space: An Ordinary Astronaut's Answers to Sometimes Extraordinary Questions are available at www.AstroClay.com. For speaking events www.AstronautClayAnderson.com. Follow @Astro_Clay #WeBelieveInAstronauts

What Do the Numbers and Letters on a Boarding Pass Mean?

iStock.com/Laurence Dutton
iStock.com/Laurence Dutton

Picture this: You're about to embark on a vacation or business trip, and you have to fly to reach your destination. You get to the airport, make it through the security checkpoint, and breathe a sigh of relief. What do you do next? After putting your shoes back on, you'll probably look at your boarding pass to double-check your gate number and boarding time. You might scan the information screen for your flight number to see if your plane will arrive on schedule, and at some point before boarding, you'll also probably check your zone and seat numbers.

Aside from these key nuggets of information, the other letters and numbers on your boarding pass might seem like gobbledygook. If you find this layout confusing, you're not the only one. Designer and creative director Tyler Thompson once commented that it was almost as if "someone put on a blindfold, drank a fifth of whiskey, spun around 100 times, got kicked in the face by a mule … and then just started puking numbers and letters onto the boarding pass at random."

Of course, these seemingly secret codes aren't exactly secret, and they aren't random either. So let's break it down, starting with the six-character code you'll see somewhere on your boarding pass. This is your Passenger Name Reference (or PNR for short). On some boarding passes—like the one shown below—it may be referred to as a record locator or reservation code.

A boarding pass
Piergiuliano Chesi, Wikimedia Commons // Public domain

These alphanumeric codes are randomly generated, but they're also unique to your personal travel itinerary. They give airlines access to key information about your contact information and reservation—even your meal preferences. This is why it's ill-advised to post a photo of your boarding pass to social media while waiting at your airport gate. A hacker could theoretically use that PNR to access your account, and from there they could claim your frequent flier miles, change your flight details, or cancel your trip altogether.

You might also see a random standalone letter on your boarding pass. This references your booking class. "A" and "F," for instance, are typically used for first-class seats. The letter "Y" generally stands for economy class, while "Q" is an economy ticket purchased at a discounted rate. If you see a "B" you might be in luck—it means you could be eligible for a seat upgrade.

There might be other letters, too. "S/O," which is short for stopover, means you have a layover that lasts longer than four hours in the U.S. or more than 24 hours in another country. Likewise, "STPC" means "stopover paid by carrier," so you'll likely be put up in a hotel free of charge. Score!

One code you probably don’t want to see is "SSSS," which means your chances of getting stopped by TSA agents for a "Secondary Security Screening Selection" are high. For whatever reason, you've been identified as a higher security risk. This could be because you've booked last-minute or international one-way flights, or perhaps you've traveled to a "high-risk country." It could also be completely random.

Still confused? For a visual of what that all these codes look like on a boarding pass, check out this helpful infographic published by Lifehacker.

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