by davinp
Metro today announced that it has begun replacing the wheels on all 7000-series railcars under new, higher standards that will allow Metro to resume regular maintenance intervals and gradually add more 7K railcars to service, with the first railcars going into passenger service this morning.
Under the new process, with concurrence from the Washington Metrorail Safety Commission (WMSC), Metro will increase the fit and press tonnage used to mount the wheels to the axles on the railcar.
Due to the 7K shortage, Metro continues to utilize its oldest, least reliable railcars in the legacy fleet. As more 7000-series railcars are completed, tested, and able to run longer between inspection intervals, Metro will gradually be able to increase the number of 7Ks in service providing customers with more reliability and comfort. This will allow Metro to eventually remove the older, legacy railcar fleet placed into service.
Pressing the wheels is an exhaustive process that requires 72 hours of work for each pair of railcars. 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 railcar, 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 railcar.
It will take several years to complete on all 748 railcars of the 7000 series fleet
https://www.wmata.com/about/news/Metro- ... andard.cfm
Under the new process, with concurrence from the Washington Metrorail Safety Commission (WMSC), Metro will increase the fit and press tonnage used to mount the wheels to the axles on the railcar.
Due to the 7K shortage, Metro continues to utilize its oldest, least reliable railcars in the legacy fleet. As more 7000-series railcars are completed, tested, and able to run longer between inspection intervals, Metro will gradually be able to increase the number of 7Ks in service providing customers with more reliability and comfort. This will allow Metro to eventually remove the older, legacy railcar fleet placed into service.
Pressing the wheels is an exhaustive process that requires 72 hours of work for each pair of railcars. 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 railcar, 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 railcar.
It will take several years to complete on all 748 railcars of the 7000 series fleet
https://www.wmata.com/about/news/Metro- ... andard.cfm