Aren't trucks much more flexible than trains? Roads are already here, they're everywhere, and they go everywhere. Rails would have to be built, and even if they were, they would never be as extensive as roads are.
Assuming comparable existing infrastructure, trains might be more efficient, but isn't it much more efficient to use the existing infrastructure, to the point that it mitigates the efficiency of a train?
According to that 2008 source (which appears to be pro-railroad) freight rail is up to four times more fuel-efficient per ton of freight delivered than freight trucking.
Assuming comparable existing infrastructure, trains might be more efficient, but isn't it much more efficient to use the existing infrastructure, to the point that it mitigates the efficiency of a train?