Hope you are doing well. As far as I understand it he is correct. Apparently there were tracks on the barge, the cars were transferred or taken aboard and then transferred to track on the other side. Don't know exactly how they worked it. Not sure where I came by this information, but I seem to remember that some of the track taken up when the Confederates evacuated Pensacola, was used for this purpose. I suspect that that The Railroads of the Confederacy and the OR's are where I sort of remember this from.