About half-ish is new track. There was an existing single track owned by the Florida East Coast Railway used by freight trains, and they are adding a second tra

About half-ish is new track. There was an existing single track owned by the Florida East Coast Railway used by freight trains, and they are adding a second track (double-tracking). But to be fair, they already owned the right of way from when it was previously double-tracked in the 1920's, so adding the second track hasn't been hugely expensive. https://en.wikipedia.org/wiki/Florida_East_Coast_Railway https://en.wikipedia.org/wiki/Florida_East_Coast_Railway