NYC subway gets a computerized facelift

NEW YORK -- A subway train rattles halfway into Manhattan's Union Square station and shudders to a halt. Over a crackle of static, a voice on the PA system announces congestion ahead and says it will be several minutes before service resumes.

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Trapped commuters sigh and glance at their watches impatiently. Some simply close their eyes in resignation.

This sort of thing -- and much worse -- has been happening quite a lot lately. Entire subway lines have recently been knocked out for hours on end by failing equipment, including decades-old switches short-circuited by flooding.

So it's no surprise that commuters are greeting with ambivalence this month's launch of fully automated trains on a 24-station line connecting Manhattan and Brooklyn.

L line trains will run without conductors, except in emergencies, coasting along at preordained speeds and stopping automatically at stations, a lone train operator in the front car watching the controls.

San Francisco has had this technology for years, and Paris has one such line.

But the New York City Transit upgrade is a milestone. Never has a city with a subway so large or so old -- it turned 100 last fall -- tried to convert its existing infrastructure to automation.

If all goes well, automation will be phased in on other lines over the next 20 years, and conductors will be phased out.

"We're moving from a 19th-century subway system," said Charles Seaton, a transit spokesman. "It's making the system more efficient, safer and allowing us to run more trains."

The new technology is not without its critics, worried about safety.

Nor has it been fast or cheap. Studies on how to convert the L line began nearly 15 years ago, and more than $250 million has been spent so far on upgrading the L, chosen partly because it's among the shortest and doesn't share track with other lines. If the program proves a success, it could take decades to implement the technology citywide.

Why go to the trouble?

Nabile Ghaly, NYC Transit's chief signal engineer, said the new system lets traffic controllers know exactly where each train is at all times, and it tightly controls train speed. With it, trains can run more closely together -- and therefore more frequently -- and with fewer accidents, transit officials say.

The new system uses "communications-based train control," or CBTC. Computers on trains, alongside tracks in special enclosures and at a new control center monitor a train's location and speed via radio waves.

As in the subway systems in Washington, D.C., and London, screens installed in stations will tell riders when the next train will arrive.

Train operators can adjust speeds themselves, but a warning flashes if they exceed limits set for specific sections of track. If the operator ignores the warning, brakes clench and the train stops -- a precaution meant to head off driver-based accidents.   Continued...