»Take the (automatic) L train

The MTA will automate the L train.
Reminiscent of the Alcatel / MUNI fiasco. BART and DC's trains have been automatically-controlled since their inception.

Next Stop for the Subway, a Fully Automated Future
By MICHAEL LUO

The subway of the future was rumbling back and forth on the Canarsie line in Brooklyn the other day. Not sleek or silent, it seemed no different from any other train. But its innards set it apart, making it groundbreaking for a transit agency long dogged by a Luddite image.

After several years of installation work and testing, New York City Transit is finally close to unveiling its first computer-controlled train line. A rollout of the $287 million system will begin in October and continue through next spring on an overhauled L line. At first, train operators will remain in control, but when the computer-based system becomes fully operational, probably sometime in May, trains will essentially drive themselves from station to station in fully automatic mode.

The spacing of trains, their speeds and when they start and stop will be entirely controlled by a complicated system of onboard and remote computers that communicate with each other via radio signals. Operators will continue to ride in the front cab in case of emergency, but their only job will be to push a button in front of them periodically to alert the rail control center that they are paying attention.

And if all goes according to plan, in a few decades hence, all New York City subway trains will run in the same way, without human help.

"This is a revolution," said Nabil N. Ghaly, chief signal engineer for the transit authority.

Although the system's benefits mainly center on being able to run more trains at higher speeds, the most important advancement will be in safety, supporters said.

"The whole idea is to eliminate human error," said Joe Bauer, a train operator instructor who has been helping test the new system.

More than a decade ago, a subway train with a drunken motorman aboard barreled through a railroad switch in Union Square and derailed, killing five people and pushing transit officials to begin exploring options for automating their aging system.

Automated trains are by no means new. In San Francisco, Bay Area Rapid Transit trains have been completely automated since the 1970's. And New York City had a fully automated train between Grand Central and Times Square for two years in the early 1960's. More recently, driverless, computer-controlled train lines have emerged in Paris, London, Vancouver, Kuala Lumpur, Singapore and elsewhere. The New York City subway, however, continues to depend on the same antiquated system of signal lights, caution flags and speed limits.

"We are seriously behind," Mr. Ghaly said.

The current system dates to the late 19th century. Tracks are divided into blocks, usually about 600 feet long, energized by an electrical current. When a train runs over a block, it interrupts the current and triggers a signal light behind it indicating that that section of track is occupied. Trains following behind will be stopped by a red light. The problem is, it is impossible to know where exactly the train is within a block of track, so it has to be assumed when coordinating traffic flow that the train is at the beginning of a block. If engineers want to run more trains through a stretch of track, more signals have to be installed, but this is possible only up to a certain point. Right now, the least amount of space between signals is about every 300 feet, except in special instances, like curves.

Another drawback of the system is that if a signal is broken, which happens from time to time, the transit authority depends on train operators following guidelines that say they can travel no faster than 10 miles per hour.

"When a signal fails, we are really depending on the rule book," Mr. Ghaly said.

If workers are doing track repairs, the transit authority also relies on train operators obeying flagmen and instructions to slow down. And the signal system only works in one direction. If a train needs to back up because of an emergency, all the trains behind it have to be cleared.

In the new system, each train on a line will have two onboard computers (one is a backup) and an electronic reader strapped to its belly. The readers are designed to pick up signals from radio transponders placed every 600 feet along the tracks. The transponders will give trains the information they need to track their locations and speeds.

Each onboard computer will in turn communicate by radio waves with computers set up in spots along the track. These track-side computers will be doing the main work of traffic regulation. The trains' onboard computers will then set down proper speeds. Meanwhile, a main computer at the new rail control center, being built in Manhattan, will monitor everything and issue commands when needed.

In October, the system will begin operating in "shadow" mode on the L line, with train operators still completely in control while engineers make sure the software is working properly. Later, over gradually lengthening segments, the computer system will begin issuing commands to the train operator about speed and travel distances, but the operator will still apply the throttle. If the train operator ignores directions from the computer console inside the cab, the computer system will take over and halt the train.

Finally, in May or June of next year, the line will move to fully automatic mode, in which the train operator will simply sit back and watch while the train moves from station to station on its own.

The new system will allow the transit authority to squeeze 20 percent more trains onto its tracks, running 30 to 31 trains per hour on a typical line instead of 26, and permit the trains to operate at higher speeds, meaning less waiting time and shorter rides for passengers. Stations will also have computer displays that will offer passengers real-time information about when the next train will arrive.

But some outside the transit authority have raised questions about whether having computers control trains is safe in New York City, given the system's age and complexity and all that can happen on the tracks.

"No subway system is like New York City's subway system," said Councilman John C. Liu, chairman of the City Council's Transportation Committee, who wants to hold hearings this fall on the system.

"Before you start having robots run our subways, I'd like to see them get the P.A. system up and running," he said. "Let's get the P.A. system working on all the subway cars and platforms. Let's get the lighting fixed on all the platforms. Let's get the MetroCard machines working fully, all the time. Get the basic stuff done first before you go into this Buck Rogers mode."

Much controversy has centered on whether the transit authority will eliminate conductors on the new trains, leaving them with only one crew member, because train operators, who no longer have to worry about running their trains, can open and close the doors, which conductors now do. Transit officials say they are still evaluating. But union officials have been issuing warnings, saying that in a time of terrorism fears, more crew members are needed on trains, not less. They point out that packed trains in rush hours can have more than 2,500 passengers. In an emergency, one crew member, located at the front of the train, would have trouble.

"It's important to be at the technology curve, but it has to be sensible," said Roger Toussaint, president of Local 100 of the Transport Workers Union.

The questions about safety frustrate those close to the project, who point out that the technology has proven itself in other cities. The project is being led by Siemens Transportation Systems Inc., the company that brought Paris the driverless Meteor Metro line, which opened in 1998. Engineers concede, however, the New York's system brings its own set of challenges. Stephane Bois, a software consultant on the project, said the biggest difficulty has been figuring out how to overlay the new system over the old, while making sure both still work.

Despite the criticism and obstacles, transit officials are moving forward with plans to convert the No. 7 line beginning in 2007 to the same computer-based system and then the F line in Brooklyn in 2009. Eventually, transit officials hope the entire system will be converted, although that could take decades.

As for the matter of making public address announcements actually understandable, they say they are still working on that.

Copyright 2004 The New York Times Company