Aluminum ACI (Automatic Car Identification) Plate / Tag and 1967 Chesapeake and Ohio / Baltimore and Ohio 1967 Internal ACI Report Aluminum ACI car tag measures 10 1/2" x 22" and while the tag does have some mild bends and broken out mounting holes, the tag does not appear to have spent many years outside. Also included is an internal report from the Chesapeake and Ohio / Baltimore and Ohio on ACI plates and their plan for implementation. The report was sent to the Chicago, South Shore, & South Bend Railroad in November 1967 and was requested to be kept internal as it discussed labor implications and other sensitive business details.