WMATA begins returning repaired rail cars to service

The Washington Metropolitan Area Transit Authority (WMATA) has begun replacing the wheels on all 7000-series rail cars under higher standards that will enable Metrorail to resume regular maintenance intervals and gradually add more 7000-series rail cars to service.

The first rail cars entered passenger service this morning, WMATA officials said in a press release.

Under the new process, WMATA will increase the fit and press tonnage used to mount the wheels to the axles on the rail car. After the cars have 20,000 miles in passenger service, WMATA will perform additional inspections, wheel measurements, and engineering analysis on the rail cars before the 7000-series are returned to standard periodic inspection intervals.

Pressing the wheels requires 72 hours of work for each pair of rail cars. Unlike changing the tires on a car, the entire wheel assembly or truck, including the axle, frame and two wheels must be removed from the rail car, similar to removing the entire front end of a vehicle. The wheels must be disassembled from the truck, and new wheels with a tighter fit installed at an increased force onto the axle before being reassembled onto the rail car.

The work requires specialized equipment, customized and calibrated to WMATA-specific production requirements and involves significant training to perform. After the wheels are pressed, the rail cars undergo up to 30 hours of detailed inspections before entering passenger service. During the follow-up engineering analysis, the wheelsets must be removed from the rail cars and taken apart for additional inspection and testing.

Under the current return-to-service plan, WMATA continues to inspect 7000-series rail cars at 30-day intervals, limiting the number of cars that can operate due to the frequency of inspections.

Once the wheel-pressing process and training ramps up, WMATA officials expect to complete about 20 cars a month. With 748 rail cars, including 5,984 wheels on 2,992 axles, officials anticipate it will take several years to return the entire fleet to normal service at an estimated cost of $55 million.