For 10 points, name this American company with ticker ADX.
It was Andrew Carnegie's first investment and its train robberies by the Reno gang brought the Pinkerton Detective Agency to national prominence. It spun off the "Southern" company during the Civil War, but it's generally believed that the northern company controlled it. Begun as a shipping company by a produce merchant ruined in 1837, it became an immense stockholder and exists today as a $2 billion investment trust. For 10 points, name this American company with ticker ADX.
It was Andrew Carnegie's first investment and its train robberies by the Reno gang brought the Pinkerton Detective Agency to national prominence.
{Adams Express} Company