The New York City Subway has had its fair share of problems lately. And I won't pretend I haven't complained loudly about the system's state of disrepair.

The subway is smelly, it's overcrowded, it's often delayed.

But there's one thing that sets the New York City subway system apart from most other transit systems in the world: It never stops running.

The MTA's 230 miles of tracks run trains 24 hours a day, seven days a week, 365 days a year. In my nearly three decades in this city, it's only shut down a handful of times. In fact, the 113-year-old system experienced its first-ever weather-related shutdown in 2011 in preparation for Hurricane Irene.

That's remarkably impressive. Most other big cities shut down their subway systems every single day.

In fact, the six largest metro systems in the world by annual ridership — Beijing, Shanghai, Seoul, Guangzhou, Toyko, and Mosco — all shut down at night.

The London Tube may have fancy turnstiles and futuristic platform screen doors, but the subway system closes every day.

New York City's subway never sleeps. Thomson Reuters The same can be said about other subway systems in the US.

Only five rapid transit systems in the country have 24-hour service, and three of them — the subway, the Staten Island Railway, and the PATH — all service New York City. Chicago's "L" is only 24/7 on some of its lines.

I appreciate the plush seats and clean floors on subway systems in cities like Boston, Washington, DC, and San Francisco. But the fact is those nice cars don't do much for the millions of people who have to get somewhere in the middle of the night.

Subway systems that shut down are more than just an inconvenience for late night revelers. For millions of night-shift workers, they make getting to work a nearly impossible feat.

Being open all night long is part of what makes New York's subway the city's great equalizer.

Wall Street bankers and janitors alike rely on the transit system. It's the fastest way to get from point A to point B. It costs the same despite how far you're traveling. Most impressive: You can rely on it at all hours of the day and it doesn't discriminate against people who work off-hours.

So say what you want about the subway. There's a lot that needs fixing and improving. But a subway system that runs 100% of the time is far superior to one that doesn't.