WMATA won’t use 4000-series railcars in lead positions after safety concern identified

Written by Kyra Senese, Managing Editor
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Inspectors do not agree with Washington Metro’s standards for restraining rails.
Ben Schumin via Wikimedia Commons

Washington Metropolitan Area Transit Authority (WMATA) General Manager and CEO Paul J. Wiedefeld has ordered the prompt removal from service of all 4000-series railcars from the lead position of trains following the identification of a possible safety issue.  

 

Representatives say the safety concern involves the vehicle’s automatic train control (ATC) system that could result in a “false indication” to a train operator going undiscovered. 

WMATA says its ATC system keeps trains appropriately spaced at a safe distance from other trains by presenting “speed commands” on a control panel in the operator’s car. When operating in “manual mode,” the train operator reacts to the speed commands, which display the train’s maximum authorized speed based on the train’s location and proximity to other trains. Operators also receive “zero speed commands,” which are indicated by a double zero, when the train is not authorized to move—the equivalent of a “stop signal.”

WMATA railcar engineers say they have reason to believe an undetectable failure of the 4000-series ATC system control board could result in improper speed commands being delegated to a train when a 4000-series car is in the lead position.

“Today’s action is being taken in an abundance of caution and, while we believe the risk is small, it is a risk I am unwilling to take,” Wiedefeld said. “Everything we do here is going to put safety first, no matter what.”

WMATA has begun the process required to remove 4000-series cars from its mainline tracks.

Based on a preliminary investigation initiated Nov. 17, WMATA says the 4000-series railcar manufacturer may recommend annual testing to minimize the risk of a false indication. Representatives say WMATA does not currently carry out such testing.

WMATA says it may consider “bellying” 4000-series cars in the center of trains, similar to operations for 1000-series cars. The transit authority says the ATC issue identified this week does not pose a risk when the 4000-series cars are not in the lead position. 

Before the recognition of this potential safety hazard, WMATA has been considering retiring all of its 4000-series railcars by the end of 2017. The transit authority may now accelerate the 4000-series retirement after realizing the newly identified safety issue.

WMATA customers may notice fewer 8-car trains in service throughout the next several days as a result of this week’s developments.

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