You’re standing on the platform at Union Square. It’s 8:42 AM. The air is thick, smelling of ozone and too many people in too small a space. Then you hear it. That low, rhythmic rumble that vibrates in your molars before you even see the headlights. Most people call it the East Side IRT. To everyone else, it’s just the 4 5 6 subway.
It’s the only heavy-rail spine serving the entire East Side of Manhattan. Think about that for a second. Millions of people, one single corridor of track. It’s a logistical nightmare that somehow, miraculously, works most of the time. If you’ve ever tried to squeeze into a 5 train at Grand Central during a rainy Tuesday rush hour, you know it’s not just a commute. It’s a contact sport.
The 4 5 6 subway isn't just a set of lines on a map; it is the highest-ridership corridor in the United States. Before the Second Avenue Subway (the Q extension) opened its first phase in 2017, these tracks carried more people than the entire transit systems of Chicago, San Francisco, and Boston combined. That’s not hyperbole. That’s the reality of New York geography.
Why the 4 5 6 Subway is Always So Crowded
Geography is destiny. Manhattan is a long, skinny island. For decades, the West Side had the 1, 2, and 3 plus the A, B, C, and D. The East Side? Just the Lex.
The 4 5 6 subway runs under Lexington Avenue, but it serves people living all the way over at First Avenue and East End. That’s a long walk for a lot of people. When the elevated lines on Second and Third Avenues were torn down in the mid-20th century, the city promised a new subway to replace them. They didn't build it for seventy years.
So, everyone crammed onto the green lines.
The 4 and 5 are the expresses. They skip the small stuff. If you're coming from the Bronx—maybe starting at Woodlawn or Eastchester-Dyre Avenue—these are your lifelines. The 6 is the workhorse local. It hits every stop from Pelham Bay Park down to Brooklyn Bridge-City Hall. It’s slower, sure, but it’s the only way to get to 28th Street or Astor Place without a massive hike.
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The Technical Wizardry of CBTC and On-Time Performance
The MTA has been slowly dragging this system into the 21st century. For years, the 4 5 6 subway relied on "fixed-block" signaling. It’s old-school tech. Essentially, a train couldn't enter a "block" of track until the train ahead of it had cleared it. This created huge gaps between trains.
Enter Communications-Based Train Control (CBTC).
This is the tech that allows trains to "talk" to each other. They can run closer together safely. On the L line and the 7 line, it changed everything. On the Lex, it’s been a harder slog because of the sheer complexity of the junctions, especially around 149th Street in the Bronx and the bottleneck at Grand Central.
Honestly, the 4 5 6 subway is a victim of its own success. When a train stalls at 86th Street because someone held the door for a friend, the ripple effect is instant. Within six minutes, there’s a backup stretching all the way to 125th Street. The system is tuned so tightly that there is zero margin for error.
Survival Tips for the Lexington Avenue Line
If you're new to the city or just visiting, the 4 5 6 subway can feel intimidating. Don't let it be.
First, know the "Grand Central Scramble." If you are transferring from the 7 or the S (Shuttle) to the Lex, do not just follow the crowd blindly. The platforms at Grand Central are narrow and dangerous when packed. Look for the stairwells at the ends of the platforms rather than the ones in the middle. They’re usually slightly less congested.
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Second, understand the 5 train's "identity crisis." During rush hours, some 5 trains go to Nereid Avenue in the Bronx, while others go to Dyre Avenue. In Brooklyn, some go to Flatbush Avenue-Brooklyn College, and others end at Crown Heights-Utica Avenue. Check the overhead signs. Getting on the wrong 5 train can end with you being very far from where you intended to sleep.
The 6 train has its own quirk: the ghost station. If you stay on the 6 after its final stop at Brooklyn Bridge-City Hall, the train loops around the abandoned City Hall station to head back uptown. You’re technically allowed to stay on. It’s one of the few places where you can see the 1904 vaulted tile ceilings and brass chandeliers of the original subway system. It’s beautiful. It’s a reminder that this grimy, loud system was once a "Palace for the People."
The Myth of the "Easy" Commute
People think if they live near a 4 5 6 subway stop, they’ve made it.
Kinda.
You’ve traded distance for density. You might only be four stops from Midtown, but you might have to wait for three full trains to pass before there is enough physical space for your body to fit inside the doors. Pro tip: if the platform is packed, walk to the very north or south ends. People are lazy. They cluster near the stairs. The middle cars are always the most crowded.
Real Data: The Lex vs. The Rest
Let’s look at the numbers. The Lexington Avenue line handles about 1.3 million riders daily. To put that in perspective, the entire Washington D.C. Metro system handles about 600,000 on a good day.
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| Feature | The 4 Train | The 5 Train | The 6 Train |
|---|---|---|---|
| Type | Express | Express | Local |
| Northern Terminus | Woodlawn (Bronx) | Eastchester-Dyre Ave / Nereid Ave | Pelham Bay Park / Parkchester |
| Southern Terminus | Crown Heights-Utica Ave (BK) | Flatbush Ave-Brooklyn College (BK) | Brooklyn Bridge-City Hall (MHTN) |
| Reliability | High (mostly off-street) | Moderate (shares tracks) | High (dedicated local tracks) |
The 6 train is often rated as one of the most reliable in the system simply because it doesn't have to merge with as many other lines as the 4 or 5. It just stays in its lane. Literally.
The Future of the 4 5 6 Subway
Is it ever going to get better?
The expansion of the Second Avenue Subway is the only real "fix." Phase 2 is supposed to bring the Q train up to 125th Street. Once that happens, a huge chunk of the ridership currently clogging the 4 5 6 subway at 86th, 96th, and 125th will migrate East.
Until then, we have the "Open Gangway" cars. The MTA has been testing R211T trains on other lines, where you can walk from one end of the train to the other without opening a door. This increases capacity by about 10%. When these eventually hit the Lex, it’ll feel like a massive release of pressure.
Also, keep an eye on the "Platform Screen Door" pilot programs. They’ve been testing them at 14th Street-Union Square. If they can successfully install glass barriers that only open when a train is present, it will virtually eliminate "track trespasser" delays and litter fires, which are the two biggest causes of non-mechanical "unplanned" service changes.
Actionable Steps for Navigating the Lex Like a Pro
If you want to master the 4 5 6 subway, stop acting like a tourist and start acting like a local who has somewhere to be.
- Download the MYmta or Transit app. Don't rely on the wall maps. The 5 train changes its route more often than a politician changes their mind. You need real-time data on whether the 5 is actually running to Brooklyn or ending at Bowling Green.
- Position yourself on the platform. At 86th Street, the stairs are at the ends. At Grand Central, the best transfer point to the S shuttle is near the front of the Uptown trains. Learn the station layouts to shave three minutes off your transfer.
- The "Empty Car" Rule. If you see a crowded platform and one car is completely empty, do not get on it. There is a reason it’s empty. Usually, it’s a broken AC unit in July or a "biohazard" situation. Trust the crowd on this one.
- Use the 6 for short hops. If you're going from 42nd to 59th, don't wait ten minutes for an express. The local comes every few minutes and you'll probably beat the express anyway because of the dwell times at Grand Central.
- Off-peak magic. The 4 5 6 subway is actually quite pleasant at 10:30 PM on a Thursday. If you have the flexibility to travel outside the 8-10 AM and 5-7 PM windows, do it. Your blood pressure will thank you.
The 4 5 6 subway is the pulse of the city. It’s loud, it’s crowded, and it’s occasionally frustrating. But it’s also a marvel of engineering that keeps New York moving. Without it, the East Side would simply grind to a halt. Respect the line, learn its quirks, and always let people off the train before you try to get on. That’s the most important rule of all.
To truly master the commute, start by checking the MTA's Weekender site every Friday afternoon. The 4 5 6 subway is frequently redirected over the Manhattan Bridge or via the 2 line during track maintenance, and nothing ruins a Saturday like ending up in Downtown Brooklyn when you were trying to get to the Metropolitan Museum of Art. Plan your route, keep your head up, and keep moving.