City's Metro Passes Round Of 'Integrity Tests'

Control And Collision Prevention System Checked

July 02, 2009|By Michael Dresser | Michael Dresser,

A Maryland Transit Administration official said early Wednesday morning that Baltimore's Metro subway had passed a round of tests of the reliability of its control and collision prevention system conducted in the aftermath of the fatal June 22 crash of two Washington Metro trains.

MTA testing engineer John Forbes said a third night of so-called "integrity tests" was completed about 3:30 a.m. and the examination had found "no anomalies whatsoever" in the speed controls on one of the two tracks from Johns Hopkins Hospital to Owings Mills.

Forbes said the other track was found to have no speed control problems the previous night, while a test of the Metro's collision avoidance system last week also uncovered no malfunctions.

The MTA invited a Baltimore Sun reporter and photographer to ride along while the tests were performed but did not let them monitor the actual examination, which was conducted in the cab of a subway train while visitors were permitted to view through a glass panel.

Forbes later said he had been reading off speed limits generated by the automated train operation system as the train passed each of about 250 signal boxes, as systems maintenance supervisor Jim Hawkins checked them against a list of correct limits and Ethel Lockhart operated the train manually.

The highest speed allowed on the Metro is 70 mph in the stretch between the Old Court and Owings Mills stations, but the testing was performed at lower speeds so each signal box could be checked off.

Gwendolyn Cole, acting chief of road services and a former subway operator, said that if the train had passed a signal box with an erroneous code, it would have stopped. But the train continued straight on through from Hopkins Hospital to Owings Mills.

The integrity tests were ordered by MTA Administrator Paul J. Wiedefeld after the collision of two Washington Metro trains on the Red Line near Fort Totten station. The crash, which killed nine people, was the worst in the 32-year history of the Washington system.

Like the Washington system, the Baltimore system normally operates under the control of a specialized computer system that regulates the speed of the train according to where it is in the system. Also standard in U.S. subway systems is a secondary computer system designed to prevent trains from getting close enough to each other to risk a collision.

Under routine operations, the human operator's job is to close the doors, put the automatic system in operation and be alert for emergencies in which it is necessary to take manual control. The National Transportation Safety Board found evidence that the operator of the moving train in Washington, who was killed in the crash, tried to apply an emergency brake before impact.

Since the crash, the Washington system has been running under the control of its human operators as investigators try to determine what may have gone wrong with its computerized systems.

MTA officials said that while the Baltimore system uses train operation and collision prevention equipment made by different manufacturers than Washington's, Wiedefeld decided to conduct the integrity tests out of an abundance of caution.

MTA officials said the integrity tests were the first to be performed on the Metro since the aftermath of an incident in late 2007 in which an operator noticed he was being given an incorrect speed limit as he entered a station.

"It's not a usual test that we do," said Forbes. "It's something to just reassure ourselves that the system is holding as we designed."

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