by YOLO
Metro is able to do this because the are running the 7000 series cars as 6 car trains.
A few years ago Metro had to take the 2000 series out of storage when they had wheel problems with the 7000 series trains.
The 2000 series trains were the last ones that still had carpet.
These cars are 40 years old and were rehabbed 20 years ago, so they are at the end of their useful lives and are becoming more unreliable as they age.
The same company that manufactured the 2000 series trains also manufactured the 3000 series trains which Metro ordered a few years after the 2000 series