Broken Laws, Bent MetroCards

I broke a law on Halloween. (Okay, so it’s conceivable that I broke several laws on Halloween, but I’m talking about something I really shouldn’t, in retrospect, have done.) It was the end of a very long day full of transportation-related debacle that included ten hours on the Fung Wah bus, a flat tire on my bicycle in Cambridge, and an outrageously expensive taxi ride from Cambridge to Boston.

Back in New York, I decided to spring for a cab home to Brooklyn, and was turned away by six consecutive drivers-- some of whom had legitimate excuses, some of whom just didn’t want to cross the bridge.

So I walked to the F train and, descending the stairs, felt the old sense of hurry and rush that everyone always feels when they get underground and hear the train coming and decide to break into a run. Except. The LED display at the turnstile informed me that my MetroCard had insufficient funds. And just as that occurred, a couple of mechanics were opening the gate and entering the station-- and this thing happened that I can’t really explain. I grabbed the door behind them, opened it, and walked through. Then I ran down the stairs and made my train.

Why did I do it, knowing that the NYPD arrests thousands of people a year for the crime? I’d like to say I was acting on instinct. I’d like to say it was the same thing that happened to Wesley Autrey last New Year’s, when he jumped onto the tracks in front of a speeding train and lay down on top of a stranger, saving his life.

I guess mine was just a less heroic instinct.

The MTA loses millions of dollars annually to fare evasion (16 million as of 2005). Mostly, people hop turnstiles, but there are also plenty of cheap scams involving unlimited MetroCards or station agents. When MetroCards were first introduced and the technology was lousier, it was easier to fool the system, and tech-geeks (and anyone who learned from them) were getting free rides all over the city.

My personal favorite of these early scams is the bent MetroCard. The idea was to take an empty card and bend it in the place on the magnetic stripe where fare deduction is encoded. This worked because, when you swipe a MetroCard, the data is read and rewritten by a series of magnetic “read heads” that perform different jobs. Magnetic read heads are these little pea-sized machines that convert the magnetic information on your card into electrical signals, and vice-versa. In fact, this technology works just like tape and video players, except that instead of the tape moving from spool to spool across the read head, your hand moves the magnetic stripe along as you swipe. This read head is a version of a simple electromagnet:

When you pass your card through the machine, an electrical pulse travels through the coiled wire and creates a magnetic field in the iron core. When the magnetic field reaches the gap in the core, a fringe pattern is created in order to bridge the gap. This fringe pattern interacts with the magnetic stripe on your card to write new information on it. The opposite process also occurs to read your card—the microscopic magnets on the stripe create a magnetic field in the iron core, which travels to the wire and sends electrical signals back through the wire.

The whole process, with different read heads performing different jobs, takes only about one-tenth of a second.

In 2005, the MTA changed the read-head technology and drove the card-bending trick into extinction. The change involved making the technology more sensitive, thus promoting MetroCard swiping to a low-level art form involving, if not beauty, a delicate combination of grace and speed.