News

A modern subway signal tower (NYC Transit)

NEW YORK, NY March 17, 2007 —Service on the 7 train is back to normal this weekend, in order to accommodate St. Patrick’s Day revelers. But that’s just a quick reprieve; service from Queens to Manhattan will be suspended again over the next few weekends. The signal system on the Seven Line is getting a 21st century upgrade. As WNYC’s Beth Fertig reports, the subways still rely mostly on mechanical systems whose origins date back a century.

REPORTER: The signals are visible to any subway passenger who looks at the track. They’re red, green and yellow just like a traffic light.

DARINO: The whole idea of the signal system is based on the safety aspect, of being able to relay information to the train operator so he can safely move his train.

REPORTER: Bob Darino is an Assistant Vice President for Operations and Training at New York City Transit. We’re in a place called Signal School, where future dispatchers and mechanics learn their trade by practicing on real equipment.

An older subway signal tower, from around the 1960s (NYC Transit)

INSTRUCTOR: What kind of energy goes on this motor:

REPORTER: This class is learning how to use an interlocking machine. It’s the same kind of machine that controls the Number 7 line: a huge black panel dating back to the 1960s with buttons and electrical relays covered in glass. The buttons control the signals. Trains and stations appear as rows of lights.

DARINO: So you see some red lights in the station. See them? That represents a train. So what I’d like you to do is I’d like you to push this button here.

REPORTER: We step behind the machine to check out the actual signal it’s controlling on a mock train track.

DARINO: And if we take a look at the signal what code do you see? REPORTER: Yellow. DARINO: Yellow. So what you’ve done to the train operator remotely from a far location, you’ve given that train operator the information that he can proceed, or she can proceed.

REPORTER: But trains can’t steer themselves. That’s why the interlocking machine also controls the track switches – which can take a train from express to local.

DARINO: Oh you got some noise now. What’s that noise? REPORTER: Is it moving to the top track? DARINO: Yes. What just moved? REPORTER: The switch. DARINO: Yes, that’s right exactly right.

Track switches were originally powered with air pumps when the subway system was built in 1904. There are still interlocking machines from that era here in the Signal School – and in a few subway yards. One looks like an old-fashioned cash register with big levers painted red, yellow and blue. But slowly and steadily, all of the older machines are being upgraded.

WILLIAMS: This train it goes into Court Square.

REPORTER: Chris Williams works at a computer where the screen display is modeled after an old interlocking machine, with rows representing train lines. Only here you just click a mouse.

WILLIAMS: We only have one possible exit so we have a green light showing that possible exit so we select that exit.

REPORTER: This is not what’s being installed on the 7 line. But track equipment, switches, and signals are all being modernized with a computer transmitting information. This will eventually lead to trains controlled with the help of computers, which is now happening on the L line. But evolution is slow. About 60 percent of the subway system has modernized signals. That’s why Transit officials hate it when people complain that New York’s old machinery is lagging behind the subways of Europe or Tokyo. Darino points out that New York has 35-thousand pieces in the signal infrastructure. And it operates 24 hours a day.

DARINO: You know it’s not a small system, NYC Transit. Many, many pieces of equipment, many, many miles of trackage that all needs a control system that’s huge. And like anything that’s that large as the modernization process goes along it keeps modernizing in steps.

REPORTER: Computer-based systems should lead to fewer mechanical breakdowns. But a train still has to wait for permission to move. Which means straphangers haven’t heard the end of announcements saying: “we’re being delayed by a red signal ahead.” For WNYC I’m Beth Fertig.