One very serious potential obstacle is the potential for height limitations on barges stacked with containers. Lock and dam upgrades will benefit all riverborne traffic, but double-stacking containers on barges will eventually require considerations of how bridges and rail overpasses spanning rivers will limit barge movements. In the short term, MARAD and state transportation regulators can help operators plan routes that avoid low bridges. Longer-term viability of this mode will require more infrastructure upgrades.
Washington should pay attention. MARAD needs to start attending meetings of the Transportation Research Board, where they can hear about the benefits of containers on waterways firsthand. Stimulus money spent on riverborne infrastructure will pay dividends for decades. Spending it to accommodate container cranes at inland ports will make some local politicians very happy.