renumbered cars

It will make it easier for emergency responders to identify the cars when WMATA wrecks them.
I'd rather WMATA just stopped wrecking them, but whatever works.

Oh, totally, but it still doesn't address the fact that the same number in two places rather than one doesn't do any harm, and it seemed a pointless effort to remove the old numbers, since they were still accurate.

I agree. Removing the old numbers seems pointless. Although if they didn't someone would expect all new cars to have numbers in all the locations.