How New York City Keeps Its Subways Running 24 Hours A Day [PHOTOS]

When it comes to New York's subway system, there's plenty to gripe about.

The Metropolitan Transportation Authority (MTA) has closed a major tunnel for more than a year to make repairs after Hurricane Sandy hit, and it's no more prepared for a major storm now than it was a year ago.

But those problems obfuscate the fact that the vast majority of the time, the trains run just fine.

It wasn't always this way. In 1984, trains averaged just 9,000 miles traveled between mechanical failures.

That's about when the MTA began putting real work into keeping trains running. Now, the MTA's Scheduled Maintenance System works to fix aging components before they fail - and has improved that number to 160,000 miles.

That's thanks to the NYC Transit employees who work at facilities in Coney Island, repairing, replacing, and rebuilding the key components that keep the 40-ton subway cars in working order.