[Brakeman]

And there is no record yet of a rail (or highway) tunnel needing to be rebuilt once constructed.

I guess replacing useless concrete ceiling panels couldn't be considered "rebuilt" either.

[Andrew Byler]

I guess replacing useless concrete ceiling panels couldn't be considered "rebuilt" either.

That would be maintenance, which is necessary on all infrastructure. You know, like patching potholes or restripping a highway or replacing a guardrail damaged in a wreck.

Rebuilding is the complete replacement of the sunk investment at the end of its useful life.