As a precaution, Washington Metropolitan Area Transit Authority (Metro) officials removed 100 of its railcars from service to inspect the operation of the car door motors, make repairs and return them to service.

Between 60 and 70 of the 4000 series railcars are in service on an average weekday and all are expected to return to use within two to three weeks.

All 4,000 cars were removed from service at the end of Friday, July 2 to allow Metro's rail experts to address a possible short in the car door circuitry that could cause the doors to open while the cars are in motion. The removal of the cars was not prompted by a particular incident, but performance tests and observations conducted by Metro's operations staff. The cars are undergoing a rigorous inspection, repair and testing process.

"This is a precautionary and proactive action to ensure the highest level of safety for our riders," said Interim GM Richard Sarles.

Metro has been attempting to simulate an occurrence of the door openings in a controlled environment in a rail yard and were able to do so late this week. At that point the engineers, maintenance experts and quality control officials were able to identify the cause of the concern as well as the needed fix. The problem is within the circuitry of the cylindrical door motors, which are about a foot long and five inches wide. In total, the 100 railcars have 1,200 motors as each railcar has 12 individual doors.

Metro engineers and mechanics will be working around the clock to test and repair all 1,200 door motors. All of the motors will be removed, inspected, repaired, cleaned, reinstalled and retested. As the cars are repaired, they will be placed back into service. It is expected to take two to three weeks to complete the work on all of the motors.